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A Guide to Surface-Mount Assembly
What automated soldering methods can be considered for Mini-Circuits surface-mount components? There are two basic methods: reflow and wave soldering. Generally, reflow soldering can be done when (1) there are only surface mount components, or (2) these are present together with through-hole components and the latter will be soldered in a separate (wave soldering) step. The surface-mount components can be located on both the upper and lower sides of the board when reflow is used. Wave soldering is suitable for through-hole components mounted on top of the board as well as for surface-mount components on the bottom of the board. Both ceramic and polymer-based boards can be accommodated.
A Practical Approach to the Design and Implementation of Scalable, High-Performance, Custom SMT Packages for mmWave Applications
After many years of research and development, electrical engineers, physicists, mathematicians and scientists have come to realize the benefits of operating communications systems at higher frequencies. Some of the most notable advances stemming from this research include: smaller circuit implementations for the same functionality; improved antenna gain for a given antenna size; and dramatic increases in data-carrying capacity. However, numerous challenges remain in implementing high-frequency circuits under real-world constraints. Among the non-trivial problems, packaging stands out.
Accelerating RF Component Selection with Yoni2® Advanced Search Engine for RF Components
Selecting RF components for a system design can be one of the more time-consuming tasks in the development cycle. To begin with, a designer may have to sift through hundreds of possible options for a suitable model. Each model represents a matrix of features and parameters with varying degrees of form, fit, and function compatibility with the design requirements. Evaluating the options may take hours or even days, and once a suitable part is identified, there’s still an element of uncertainty as to whether another model may have achieved better system performance. It’s the proverbial needle-in-a-stack-of-needles problem.
Achieving First-Spin Success in LTCC Components with Advanced Material Simulation Models
Since the advent of Network Synthesis Theory at the turn of the last century, filter designers have been developing ever more sophisticated solutions to translate polynomial transfer functions into working, physical components.
Adapting Non-Sealed Surface Mount Parts for Hi-Rel Customer Assembly Processes
The perfect integration of a product within the customer’s assembly process can be just as critical to the success of that product asthe electrical performance. Mini-Circuits and many RF/microwave component manufacturers build surface mountcomponents that are soldered onto customers’ PC boards using a reflow process. Following reflow, the board must be cleaned to remove solderballs, flux, salt deposits and other debris. While a number of cleaningmethods exist, the industry – and especially manufacturers of equipment for military and other hi-rel applications – have gravitated towards aqueous wash. A conformal coating is then applied to protect the circuit from moisture and other adverse environmental conditions. This process poses unique challenges for the integration of surface mount parts into customer assemblies, particularly components with open and semi-sealed case styles.
Advanced Microwave Amplifier Models for Advanced Design System Simulations
Mobile and wireless communication has seen phenomenal growth over the past two decades. Faster communication with higher data rates has been the driving factor. To achieve this, the RF front end components have been continuously improved to meet the linearity and power requirements and a range of wireless standards have emerged, based on variations in frequency, modulation and power level requirements. The 0.7 GHz to 6 GHz band has been the mostly widely used frequency range for mobile and wireless communications using different standards such as GSM, CDMA, WCDMA, LTE, WLAN and WiMAX. The evolving 5G standard is pushing frequency ranges for emerging commercial systems upward to mm-wave frequencies as high as 86 GHz! Still, the bulk of near term 5G developments will likely be at the proposed bands of 28GHz and below.
The insertion loss curves for the conventional filter exhibit an expected increase in stopband rejection when two filters are cascaded in series. However, obvious ripple appears across the stopband in the two-section curve. This is due to the unstable phase relationship between the through-signal and reflected signal. Additionally, unwanted ripple is present in the passband close to the band edge of the two-section curve. This is a result of return loss degradation in the passband and reflections in the transition. By contrast, the insertion loss performance for the reflectionless filter repeats itself nicely when cascaded in 2 and 3 sections without any of the ripples or distortion seen in the case of the conventional filter.
Figures 5e through 5h show the effect on return loss when the two types of filters are cascaded in multiple sections. The conventional filter exhibits significant degradation in input and output return loss in the passband when cascaded in two sections – by as much as nearly 20 dB in some regions. When the reflectionless filter is cascaded in two sections, on the other hand, input and output return loss varies over the passband, but the same degradation is not evident, and return loss actually increases at some frequencies relative to that of a single filter. This illustrates that an improvement in return loss in the passband and the stopband can be realized by cascading reflectionless filters versus conventional filters.
Affordable Solutions for Testing 28 GHz 5G Devices with Your 6 GHz Lab Instrumentation
The capabilities that define the 5G wireless standard will require utilization of wider bandwidths across more regions of spectrum than any current wireless technology. 5G communications will eventually occupy multiple bands from below 6 GHz to above 60 GHz. For now, much of the development effort is divided among sub-6 GHz bands for vehicular connectivity and longer-range transmissions, and the 26, 28, 38 and 60 GHz bands for enhanced mobile broadband applications. The migration to higher frequencies and the multi-band nature of the technology pose a variety of unique challenges for designers developing 5G devices and network equipment. Significant among these is the high cost of instrumentation for test and measurement over such a wide range of frequencies.
An Interview with Mini-Circuits Founder and CEO, Harvey Kaylie
Q: Defense and military applications have always been a crucial segment of the global market for RF and microwave products. How do you see the defense market evolving in 2018 and beyond as compared to recent years?
Technical excellence at Mini-Circuits is coming into sharper focus as we approach the fifth decade since our founding by Harvey Kaylie in 1969. This focus has been emphasized in our current initiative to recertify our quality management system (QMS) to the new revision of AS9100. As you may expect, Mini-Circuits places the highest priority on product quality, and this has had many benefits for us and our customers. Our customer returns have been consistently below 10 PPM over the past year, and we will continue finding ways to drive this metric even closer to zero.
Bridging the Gap between the University and the RF Industry
With 5G standards barely off the drawing board and headlines filled with speculation about all the related capabilities, what sometimes gets lost in the buzz is that these technologies will depend heavily on a new generation of RF engineers to develop the circuits and systems to realize the dream. It is difficult to conceive of the number of new products that will incorporate high-speed, wideband RF communication once next generation wireless networks are rolled out, and the industry needs a deep pool of technical talent to support the demand.
Choosing the Right RF Coaxial Cable Assembly for Your Application
Selecting the right RF/microwave cable assembly can be a confusing task considering the variety of products on the market and the multiple characteristics of each. Adding to the challenge, many products don’t lend themselves to a straightforward, “spreadsheet” comparison. This guide was written to go beyond the spec sheet and help you find the right cable for your needs more quickly and more knowledgeably. We will review the different categories of RF cables and their attributes and provide some guidelines on how to prioritize parameters for your application. Note that we omitted fundamental RF theory because much has been written on that subject and this is meant to be a practical resource for engineers in the field rather than a study guide. We also omitted corrugated and CATV coaxial cable as those are typically used for niche applications.
Combining MMIC Reflectionless Filters to Create Ultra-Wideband (UWB) Bandpass Filters
Ultra-Wideband (UWB) radio is defined as any RF technology utilizing a bandwidth of greater than ¼ the center frequency or a bandwidth greater than 500 MHz  . While UWB has been a known technology since the end of the nineteenth century, restrictions on transmission to prevent interference with narrow-band, continuous wave signals have limited its applications to defense and relatively few specially licensed operators . In 2002, the FCC opened the 3.1 to 10.6 GHz band for commercial applications of Ultra-Wideband technology, and since then UWB has become a focus of academic study and industry research for a promising variety of emerging applications. To prevent interference with neighboring spectrum allocations like GPS at 1.6 GHz, the FCC has imposed specific rules for indoor and outdoor transmission of UWB signals, limiting transmissions in the permitted frequency range to power levels of -41 dBm/MHz or less.
Compensating Frequency-Dependent Cable Loss in CATV Systems with Mini-Circuits Voltage-Variable Equalizers
In broadband communications systems such as CATV equipment, system performance may critically rely on gain or attenuation flatness. In particular, CATV systems are often plagued by issues resulting from the frequency-dependent attenuation of very long cables (increasing with frequency) as well as the negative gain slope of certain amplifiers. This negative gain slope exhibited by CATV system components can cause a variety of headaches for system designers.
Demystifying Pin-Outs: What Do We Mean by “Not Connected?”
Mini-Circuits offers a wide range of products in miniature surface-mount (SMT) packages. Each package is identified by a case style number and defined by a case style drawing which clearly shows the outline dimensions, critical dimensions (if any), orientation, pin numbering, pin-out details, and material finish wherever applicable.
Some case styles are used in various Mini-Circuits products, and different signal pads may be used depending on the circuit design of each model. In some cases, some signal pads on the unit may be left unused and marked as “NOT CONNECTED” in the pin-out details on the datasheet.
This article explains by way of example what we mean when we denote signal pads this way, and how users may treat these pads when mounting the part on their board.
Demystifying RF Transformers: A Primer on the Theory, Technologies and Applications – Part 1
In essence, a transformer is merely two or more conductive paths linked by a mutual magnetic field. When a varying magnetic flux is developed within the core by alternating current passing through one conductive path, a current is then induced in the other conductive paths. This induced current is proportional to the ratio of magnetic coupling between the two conductive paths. The ratio of the magnetic coupling of the conductive paths with the core determines the induced voltage in the additional conductive paths, providing both an impedance transformation and a voltage step-up or step-down. Additional conductive paths, potentially all with different coupling ratios, may be added to realize various functions, which is why RF transformers are such varied and versatile devices used widely throughout the RF/microwave industry.
Baluns and ununs are essential in RF signal chains for many applications. RF balun designs are most commonly associated with core-and-wire transformers, but can also be realized through coaxial and coupled stripline technologies. The behavior of baluns and ununs was introduced in Part 1 of this series, where we established that both these devices are designed for impedance matching purposes. The major difference between them is that baluns are designed to match impedances between balanced and unbalanced circuits, whereas ununs provide impedance matching between two unbalanced circuits.
Directional Couplers: Their Operation and Application
Directional couplers are important devices in RF systems. Their ability to sample either the forward or reverse direction of signal propagation allows a wide range of applications in test, measurement, monitoring, feedback and control. This note should help system designers understand the function, architecture and performance of the coupler, to select a suitable type for their particular application.
Eliminating Bias Tees from Push-Pull Amplifier Outputs Using TCM3-452X+ 3:1 Unbalanced-to-Balanced Transformer
Push-pull amplifiers are used in many multi-octave systems to enhance amplifier output power and efficiency, suppress unwanted harmonics and improve system dynamic range. In a push-pull amplifier design, two matched transistors or amplifiers are supplied by the source signal in parallel and at a 180° phase relationship. When re-combined through a second 180° phase shifting combiner, the fundamental signals are in-phase and combined at twice the power of each half, while the even order harmonics are out-of-phase, creating ideal cancellation of these unwanted signals. In reality, the phase and amplitude unbalance of the splitting-combining circuits result in degradation of the ideal cancellation. However, the net result is still significant suppression of the even harmonics, typically by 20 to 40 dB.
Extending the Performance and Frequency Envelope for QFN Packaging Technology
High-performance, millimeter-wave (mmW) Monolithic Microwave Integrated Circuit (MMIC) products and cost-effective surface mount lead-frame-based packaging typically don’t come up in the same conversation, and for good reason. Just two to three years ago, it was difficult to conceive of operating at frequencies above 20 GHz without considering an expensive, open cavity, High Temperature Co-fired Ceramic (HTCC) package or resorting to more bespoke chip and wire assemblies.
FILTERING WITHOUT REFLECTIONS: Flattening Multiplier Chain Conversion Efficiency & More
A new class of filter, which exhibits broadband matched impedance at its ports, has recently been invented and made available. This new device, the reflectionless filter, has demonstrated a variety of benefits when used to replace conventional filters in a signal chain. This white paper briefly introduces the reflectionless filter and compares conventional filter and reflectionless filter behavior. Use cases are presented examining how reflectionless filters can improve system performance when used with mixers, ADCs, and receiver signal chains. Lastly, an experiment is described and test results presented to compare the conversion loss ripple in multiplier chains when reflectionless and reflective filters are used to filter spurious signals.
Flattening Negative Gain Slope with MMIC Fixed Equalizers
Equalizers are devices used to compensate for negative gain slope in the frequency response of a wide variety of RF systems. Unlike a standard attenuator with a flat frequency response, an equalizer is a unique kind of attenuator which exhibits lower insertion loss as frequency increases with some known slope. This is a useful characteristic for system designers working in wideband applications where the gain response of circuit elements or of the entire RF chain often varies across frequency.
Frequently Asked Questions About Power Detectors
Q. I recently purchased a PWR-6G power detector and was wondering if I need to have it calibrated, or if it came to me calibrated.
A. The PWR-6G+ is calibrated prior to shipping and therefore there is no need for calibration of new power detectors. A customer can start working once the power sensor software has loaded and the USB cable is plugged in to the computer. We recommend sending the PWR-6G+ once a year for calibration.
The extreme operating conditions of the space environment combined with lack of access for repairs and zero tolerance for failure necessitate intensive qualification of electronic parts used in space missions. Mini-Circuits has a successful track record of screening components for space applications, and our experience in this area has led to robust testing and qualification programs for the parts we supply for these systems.
Testing cellular network infrastructure often requires measurement and data collection from dozens – even hundreds – of base stations (BTS) within a test environment. The volume and complexity of signal traffic in these multi-device, multi-user test systems necessitates commensurate capability for routing signals between base stations and test stations. By partnering with customers to lower costs and improve efficiency in high-volume test systems, Mini-Circuits has developed a line of high-order switch matrices supporting a wide variety of switching configurations and control methods. This article will present a case study of a 20 x 6 non-blocking, full access switch matrix used to facilitate signal routing in a cellular network test system with extensions for other applications.
High-Q Ceramic Resonator Filters for GNSS Applications
GNSS (Global Navigation Satellite Systems) has become an increasingly prevalent RF application for both military and consumer use. Early GNSS technology, or location-based services (LBS), was developed exclusively for military use and operated with a margin of error of about 10-yards (9.14m), which was sufficient at the time, but limited its suitability for end uses requiring a higher degree of precision. In the time since the first launch of GPS more than 40 years ago, the evolution of the technology has improved precision to the order of 2-3 yards (1.83-2.74m). This advancement of the technology combined with significant miniaturization and cost reduction of LBS-enabled devices has opened up a large and growing commercial market for GNSS services. For example, GNSS is now used in the agricultural market to calculate statistics for weather, soil conditions, and crop health to help farmers maximize their yields and profits. Such innovations have stimulated demand for components that support military, industrial and consumer applications.
Impact of Date Code Age Restrictions on Quality, Service, and Value
Extensive studies done by industry leaders, NASA and the U.S. military have shown substantial evidence that in modern storage environments, time intervals of five years or longer between manufacture of components and shipment to OEMs pose virtually no risk to the quality or reliability of electronic products. Date code based age restrictions were originally imposed due to concerns about age-related oxidation of eutectic (or tin-lead plated) parts and loss of component solderability. The subsequent replacement of tinlead solder with lead-free solder in RoHS compliant parts has since minimized the cause of this failure mechanism. Additionally, advances in product packaging and storage such as bagging, taping, and moisture control techniques now provide robust protection from electronic degradation and “out-of-the-box” failure due to age for time periods in the order of decades (i). As a result of such findings, the US military has eliminated date code requirements for electronic products altogether (ii), and NASA has significantly relaxed its standards, allowing a five year window before parts in storage are reviewed to determine the need for re-screening (iii).
The impedance of a component or transmission line is a major concern when designing RF/microwave systems. At the circuit level, optimum performance is obtained when devices are matched to the desired system impedance, typically 50Ω or 75Ω. At the system level, each building block must be matched to the system impedance to maintain performance along the signal path.
Mini Circuits manufactures a comprehensive line of connector gauges for measuring the critical interface dimensions of coaxial connectors .Testing the interfaces of connectors on any device at incoming inspection is not only highly recommended, it is definitely a necessity. Interfaces not meeting the specifications will lead to degraded specification of the components. In addition, these out of specification interfaces may damage the connectors of mating components or ruin the connectors of the test equipment. These connector gauges consist of an exclusively developed dial indicator with appropriate bushings and pins, designed to mate with the specific connector under test. The indicator is set to zero by a calibration block (master).When engaged to a connector, it measures the specific interface dimension from a reference plane.
Voltage Controlled Oscillators (VCOs) are normally designed for operation in an ideal 50 ohm environment. However, the actual load that these oscillators must drive are considerably different. It is a standard industry practice to measure frequency variation when the VCO output realizes a load with 12dB return loss (for all possible phase angles). This is usually performed as a manual measurement and is very time consuming. It may take a skilled technician several minutes to several hours. Fortunately, with the development of a novel electronic line stretcher from Mini-Circuits, these once tedious tests can now be executed quickly and a automatically.
Mini-Circuits Bridging the Gap Between the Classroom and the Lab
With a history that dates back 50 years, Mini-Circuits is one of the most recognizable names in the RF/microwave industry. Known as a supplier of high-frequency components, Mini-Circuits offers an enormous number of products, which includes the likes of amplifiers, filters, mixers, and couplers, just to name a select few.
Minimizing Impedance Mismatches with Fixed Attenuators
Fixed attenuators are invaluable problem-solvers for circuit-level and system-level designers. In addition to controlling amplitude levels, fixed attenuators can improve the impedance match between impedance-sensitive devices such as amplifiers and filters, and provide the isolation needed to stabilize oscillators.
MMIC Amplifiers Stretch the Boundaries of Dynamic Range in VHF/UHF Communications
The noise figure and linearity of low noise amplifiers are critical factors in maximizing sensitivity and dynamic range in RF receiver design. The amplifier noise figure determines the weakest signal the amplifier can discern, and the IP3 determines the degree to which intermodulation products from nearby signals interfere with the desired signal. The lower the noise figure and the higher the IP3 of the amplifier at the receiver input, the greater the sensitivity and Spurious Free Dynamic Range (SFDR) of the receiver.
MMIC Die Testing Made Easy with Ultra-Wideband 0 dB Attenuator (Thru-Line) Dice
Microwave hybrid circuitry is generally built by integrating several discrete dice via wire bonding. Circuit designers are faced with the task of predicting the performance of hybrids, which comes with some specific challenges.
Prior to developing our mechanical switch, Mini-Circuits purchased a significant quantity of mechanical switches for use in our production test facilities. These switches utilized a combination of springs and solenoids to accomplish the switching. Most operated for less than 1 million cycles, or approximately 50 days in our production environment. This turnover prompted Mini-Circuits to develop our own design to address the short operating life, long lead times, and high cost of using commercially available mechanical relay switches.
Modeling Grounding and Substrate Effects in Broadband Miniature Surface Mount Attenuators
Modelithics and Mini-Circuits have collaborated to create Microwave Global Models™ for Mini-Circuits’ YAT and RCAT broadband surface mount attenuator families. These attenuators can be used to reduce signal levels, increase isolation, or improve impedance-match and retur-loss performance. Both the plastic QFN package style YAT Series and the hermetic, ceramic cavity RCAT Series are available in a tiny 2mm x 2mm footprint. The key to Mini-Circuits’ YAT and RCAT attenuators’ small size, excellent uniformity, and 2W power rating is the GaAs semiconductor fabrication process having through-wafer Cu metallization vias to realize low thermal resistance and wideband operation. Available values range from 0 to 30 dB and these components are well matched to 50 ohms over the entire DC to 18/20 GHz specification range.
More than Just a Phase: Understanding Phase Stability in RF Test Cables
One important factor in ensuring accurate, repeatable measurements in RF test applications is the stability of performance of the test cable used. In most test environments, cables undergo frequent bending during normal use, which can result in changes in phase and other performance parameters. Depending on the cable, these changes can be significant enough to degrade the accuracy and precision of your measurements. Therefore, in choosing the right test cable for your needs, it’s important to consider how bending affects cable phase performance and how a cable is (or isn’t) qualified for stability of phase versus flexure.
Reflectionless Filter Basics: A Brief History of the Genesis of Reflectionless Filters
The advent of broad bandwidth amplifiers, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and software-defined radios has brought about growing interest in broadband communications, radar, and sensing applications. For these applications, there is often a need to preserve the highest sensitivity and dynamic range possible within the receiver signal chain and to mitigate the number and strength of harmonics and spurious content in the transmitter signal chain. This is a substantial challenge considering the nature of non-linear components within these circuits, namely compression-mode amplifiers, mixers, multipliers, and frequency-conversion electronics.
Reflectionless Filters Improve Linearity and Dynamic Range in Microwave Systems
Filters are fundamental building blocks of nearly every modern RF/microwave system used to eliminate unwanted signals in receiver and transmitter architectures. Until recently, study and research in practical filter design has been largely devoted to topologies in which rejection of stop band frequencies is accomplished by reflecting undesired signals back to the source. Meanwhile, there are many applications in which these reflections produce intermodulation products, gain ripples, and other problems in system performance. For example, non-linear devices such as mixers, multipliers and high-gain amplifiers which respond to out-of-band frequencies are highly sensitive to the reflections caused by conventional filter designs. This becomes especially challenging as filters are often needed near or adjacent to active devices in the signal path to better define bandwidth or suppress unwanted harmonics.
Reflectionless Filters Minimize Switching Transients in Wideband ADCs
Designers are finding new techniques to improve system performance with Mini-Circuits’ patented reflectionless filters all the time. Among these, supplementing anti-alias filters in wideband ADCs to minimize the effect of switching transients has emerged as a popular use case.
Renewing Our Founding Values as a 50-Year-Old Startup
The Mini-Circuits story is well known to many in the RF and Microwave industry. Some know us for our advertising, some know us as one of the first companies to transform the pricing structure of RF components, and some know us through the personal relationships they had with Harvey Kaylie, our founder and chief executive for the first 50 years of our history.
Selecting High Linearity MMIC Amplifiers for use with Complex Digital Waveforms
Enhanced Mode GaAs PHEMT (E-PHEMT) based MMIC amplifiers provide users advantages in both broadband noise figure and intermodulation performance, setting them apart from previous generations of GaAs amplifier designs. Historically known for their extremely low noise figure, PHEMTs have also been used extensively for power applications in the mobile PA market. Recent designs possess a combination of low noise and excellent suppression of intermodulation distortion, which improves both ends of the dynamic range over broad frequency range.
Solid State Switching for Next Generation Wireless Test Applications
Rapid growth in the number of connected devices for next generation wireless applications is driving demand for faster, more innovative, and more cost-effective test solutions. The need for reduction in cost and improvement in test throughput is found both at the design verification stage as well as in high-volume production testing. Test engineers are looking for ways to reduce the number of device-under-test (DUT) connections and enable testing of multiple DUTs in parallel from a single test station. This is most often achieved by configuring RF switches in a switch matrix to automate the routing of test signals. This article will explore some of the key differences between the types of switches used in test applications. Switch matrix configurations will be discussed, and a real world switch matrix for a high-volume telecom test application described in detail.
Specifying VCOs for Clock Timing Circuits | Application Note
Timing is everything for many systems, especially for modern electronic systems with high-speed data converters and high-resolution sampling. A clock source is “the keeper of time” in these systems and system timing performance is very much dependent upon the performance of its clock source. For some system designers, a clock source automatically means a crystal oscillator, typically a single-frequency source. But some system designers, especially those faced with synchronizing systems at multiple clock frequencies, have learned to appreciate the flexibility of using voltage-controlled oscillators (VCOs) as clock sources.
Stabilizing Multiplier Chain Conversion Efficiency with Reflectionless Filters
Frequency translation devices such as multipliers and dividers are used to convert frequencies from lower spectrum regimes to higher frequencies, and vice versa. As these devices are intrinsically non-linear, they generate spurious harmonics, which are often filtered to prevent harmonics from appearing in-band. Using conventional, reflective filters creates an undesirable scenario where the out-of-band harmonics are reflected back to the multiplier. The multiplier is also affected by the reactive loading exhibited by a reflective filter at harmonic frequencies (see Figure 1). Given that multipliers have poor output return loss, this combination of effects leads to large ripples in the conversion efficiency of a multiplier chain, and hence, susceptibility to environmental factors.
This issue can be solved by leveraging the unique capabilities of reflectionless filters. To demonstrate this solution, an experiment was conducted with a doubler test circuit and a 4X multiplier chain (see Figure 2). Each experiment was conducted using comparable reflective and reflectionless filters, and the results were then analyzed.
Impedance matching is a complex subject cloaked in a certain degree of mystery. Whenever a circuit fails or systemic problems are encountered, impedance matching is most often attributed as the cause. As a result, there are many situations in which it becomes necessary to match the impedance of a load to that of the source in order to maximize power transfer. There are many different techniques for impedance matching, and the best application of each will depend on the situation. This article will review the basics of impedance matching and describe some of the effective techniques commonly used to overcome impedance mismatch in a circuit.
Semiconductor non-hermetic packages have the tendency to absorb moisture. During the surface-mount solder reflow process, moisture trapped in the package will vaporize when heat is applied. The expansion of this trapped moisture creates internal stress, which can cause damage to the non-hermetic package. The damage can take the form of internal separation between the plastic and die or metal frame, wire bond damage, die damage or internal cracks.
Before discussing filter designs and differentiating any given filter topology from another, it’s important to review the fundamentals of filter structures and their function. A filter is a two-port, passive, reciprocal device that allows frequencies within a given band to pass through while blocking signals outside the desired band.
There are many filter types available to the system design engineer including RLC filters, active RC filters, crystal filters, cavity filters, ceramic resonator filters and SIW, SAW and BAW filters. Filters may be fabricated using lumped elements, thin and thick film microstrip and stripline, LTCC and other manufacturing technologies. This article will focus on lumped element filters.
Understanding Power Splitter/Combiner Power Handling with Coherent and Non-Coherent Signals
A Power Splitter/Combiner is a passive device that can be used for two reciprocal functions: a single signal may be divided into multiple outputs, or in the opposite direction, multiple input signals are combined into a single output. In case of an N-port splitter, the input signal will be divided into N output ports. When used as an N-port combiner, the N inputs will be combined into an output signal from a single port.
Power amplifiers (PAs) boost input signals using different amplification schemes depending upon application requirements and the nature of the signals to be boosted. Signals may be continuous wave (CW) or many forms of pulsed waveforms, with different pulse widths and duty cycles. Different signal types have different amplification needs in terms of output power, gain, efficiency, linearity, and other performance parameters.
The main reason for the utilization of surface mount technology today is for PWB area efficiency and the corresponding reduction of the system volume. Small surface mount components are used to manufacture electronic assemblies that are significantly smaller than the similar function assemblies using thru-hole components. Usually, the board area for most systems can be reduced by a factor of two for a single sided board. When components are mounted on both sides of the board, size reduction by another factor of two can be achieved. Conversely, the functional density can be doubled in the same area with the use of surface mount components. Since the height of surface mount components are generally smaller, significant reduction in system volume can also be achieved. Fewer, denser assemblies and correspondingly fewer connectors, less mechanical hardware and shorter lead lengths can yield another reduction factor of 2 to 4. Add to that the use of Application Specific IC’s (ASIC’s), and a total volume amounting to approximately 20% of the original system can result.
Using Mini-Circuits Switch Matrices in 75Ω CATV Test Applications
The 75Ω equipment often used in CATV applications occupies a small enclave of a largely 50Ω world. Although dedicated 75Ω equipment does exist, its availability and its applicability to other test needs are limited; most general-purpose test and measurement equipment is designed for 50Ω use. Because of this, it can be difficult to create test setups entirely out of dedicated 75Ω test equipment.
פיזור המסתורין מעל שנאי ת”ר חלק 2: שנאי Balun ו- Unun
שנאי Balun ושנאי Unun מהווים חלקים חיוניים בשרשרות האותות בת”ר (RF) עבור יישומים רבים. תכנונים של שנאי Balun נקשרים בדרך כלל לשנאי ליבה וחוט, אם כי אפשר גם לממש אותם בטכנולוגיות של קווים קואקסיאליים וקווי Stripline עם צימוד. ההתנהגות של שנאי Balun ושנאי Unun הוצגה בחלק 1 של סדרה זו, כאשר קבענו ששני סוגי התקנים אלו מתוכננים למטרות של תיאום עכבות. ההבדל העיקרי בין השניים הוא בכך, ששנאי Balun מתוכננים כדי ליצור תיאום עכבות בין מעגלים מאוזנים למעגלים לא מאוזנים, בעוד ששנאי Unun מספקים תיאום עכבות בין שני מעגלים לא מאוזנים.
חלק 1 של הסדרה שלנו “פיזור המסתורין מעל שנאי ת”ר” דן בתיאוריה הבסיסית וביישומים של שנאי ת”ר. מאמר זה פונה לחקירה מעמיקה יותר של שנאי Balun ושנאי Unun, כשעיקר המוקד הוא בשנאי Balun בגלל השכיחות היותר גדולה שלהם ביישומים של העולם הממשי.
פיזור המסתורין מעל שנאי ת”ר חלק 3: משמעות הפרמטרים של שנאי ת”ר
שני החלקים הראשונים של המאמר ‘פיזור המסתורין מעל שנאי ת”ר’ הציגו סקירה בסיסית של התיאוריה סביב שנאי ת”ר (RF) והיישומים שלהם וכן, העלו דיון עמוק יותר בעניין שנאי Balun לת”ר. חלק זה מספק הסבר לגבי פרמטרי הביצועים הבולטים יותר של שנאי ת”ר ותרשימי נתונים שמציגים את הדרך שבה קובעים את הפרמטרים האלו. הכרת הפרמטרים העיקריים האלו חיונית בעת בחירת שנאים עבור יישום, וכן כאשר עורכים השוואה בין דגמים שונים של שנאים.