Wideband Connectorized Amplifiers for mmWave Over-The-Air (OTA) Transmitter & Receiver Testing

Figure 1: Simplified diagram of a total radiated power (TRP) test setup.

The advent of 5G networks has already begun ushering in a whole new generation of wireless devices and applications, and device manufacturers are racing to be the first market. In order to meet the 5G standard for commercial wireless communication, device manufacturers need to develop powerful transmitters and receivers that operate in the millimeter wave range, which comes with a number of challenges, one of which is testing and qualification. Due to the wireless nature of these devices, manufactures need to conduct testing in real-world conditions, which isn’t possible using the conventional approach of connecting devices under test (DUTs) to instruments with coaxial cables. Over-the-air (OTA) allows engineers to more realistically simulate real-world device performance in the lab environment.

Distributed RF Amplifier Designs for Ultra-Wideband Applications

Figure 2: Noise figure and gain circles on the source reflection plane.

Amplifiers are used in RF systems to boost the power level of a signal. Conventional RF amplifiers are designed using reactive elements to achieve matching to the characteristic impedance of a circuit within the specified operating frequency range for a given system. Reactively matched amplifiers allow designers to optimize performance parameters for a broad range of system requirements. Combined with techniques like balancing, using 90˚ hybrids and negative feedback, they can support bandwidths as wide as about 10:1.

Novel MMIC Splitter/Combiner Designs Achieve High Isolation Down to DC

Figure 1: Resistive power splitter / combiner circuit schematic

Traditionally, DC power splitter / combiner circuits are implemented with resistors. A simple resistive power splitter / combiner circuit schematic is shown in Figure 1. If Z0 = 50W, and ports 2 and 3 are terminated in 50W, then port 1 is matched to 50W as well, so Z0 / 3 = 16.7W. Resistive power splitter / combiner circuits typically have poor isolation between ports at DC and over frequency.

MMIC Amplifiers with Shutdown and Bypass Features De-Mystified

Figure 1: Simplified schematic of an RF amplifier with shutdown functionality

Mini-Circuits’ TSS- and TSY-families of MMIC amplifiers feature a versatile combination of performance characteristics including high dynamic range and very low noise figure with wideband frequency coverage from VHF up to mmWave applications. These product families also include additional features of shutdown and bypass functionality. These features often lead to customer questions about the difference between bypass and shutdown, which products have which features, and the benefits of each. This article will explain how these features work, and provide an overview of some of the applications are where shutdown and bypass functions are most commonly used.

MMIC Technologies: Pseudomorphic High Electron Mobility Transistor (pHEMT)

Figure 2: GaAs primitive cell

Pseudomorphic High-Electron-Mobility-Transistor (pHEMT) is one technology Monolithic Microwave Integrated Circuit (MMIC) designers and fabs use to develop and manufacture microwave integrated circuits. pHEMT has gained popularity as a building block of many MMICs produced by electronics manufacturers like Mini-Circuits due to its superior wideband performance characteristics including low noise figure, high OIP3 and excellent reliability up to 40 GHz and beyond. pHEMT uses heterojunctions between semiconductors of different compositions and bandgaps to achieve outstanding high-frequency performance. This article delves into the physics of pHEMT operation, advantage, and reliability test results. A link to a summary of Mini-Circuits’ pHEMT products is also provided.

Positive Gain Slope Amplifiers Compensate for Gain Roll-Off in Wideband Systems

Figure 1: Effect on overall gain response of negative gain slope of three amplifiers cascaded in a receiver chain.

Meeting gain roll-off and gain flatness requirements over frequency is a common problem in many modern-day discrete RF transceivers. Ideally, the gain in the signal path of an RF transceiver should be flat over frequency in the band of interest. However, each component in the RF line-up has a finite bandwidth, which can cause the overall system gain response to roll-off over frequency. This is seen as negative slope in a graph of gain versus frequency. This behavior makes meeting gain flatness specifications for these transceivers very challenging to achieve, particularly over wide bandwidths.

LTCC Meets 5G: Advanced Filter Designs Achieve True mmWave Performance

Figure 3: S21 response for the BFCQ-3582A+ millimeter wave band pass filter supporting the 5G n260 band.

Low Temperature Co-fired Ceramic (LTCC) substrate technology is one major area of Mini-Circuits’ R&D investment. As a result of its long-term investments in materials, manufacturing processes, simulation and testing capability, research on novel circuit topologies, and world-class engineering talent, the company has developed a new series of filters based on LTCC technology that support the millimeter wave (mmWave) 5G market with a small footprint, low cost, and superior performance to competitive products and technologies. This includes the newly developed bandpass filters specifically designed for the 5G FR2 n257, n258, n260 and n261 bandwidths, low pass filters supporting bandwidths from DC up to 30 GHz and beyond, and high pass filters with passband cut-offs up to 36 GHz at the time of this writing.

A Primer on RF Semiconductors (MMICs)

A Primer on RF Semiconductors (MMICs)

A Primer on RF Semiconductors (MMICs) Radhakrishna Setty, Technical Advisor Introduction Semiconductors are ubiquitous in modern society. In addition to microprocessors for computing technologies, they are used in practically every active wireless communications system including cell phone towers, cell phones, radars and satellites to name a few. Mini-Circuits designs and produces several semiconductor-based (MMIC) components […]

LTCC Filters Enhance Differential Circuit Designs

Figure 1: Typical RF transceiver using discrete components.

Today’s analog-to-digital converters (ADC) and digital-to-analog converters (DAC) are typically differential circuit designs. Differential circuits provide many advantages over single-ended designs, including common-mode rejection of thermal noise, even order harmonics, and power supply noise and spurs. Additionally, differential circuits allow for half the voltage swing on each output compared to a single-ended design. Discrete transceivers on the other hand are often designed with single-ended, 50Ω matched components such as low noise amplifiers (LNAs), mixers and IF gain amplifiers. To interface with a differential ADCs or DACs, a single-ended-to-differential, or differential-to-single-ended, a transformer or balun is needed.

Peak and RMS RF Power Detectors for High-Frequency Signal Measurement

Figure 3: ZV47-K44+ package

Power detectors are widely used RF components that convert an RF input signal into an output DC voltage proportional to the RF input power. Power detectors are useful for a number of applications that include automatic gain control circuits, transmit antenna power monitoring, protecting sensitive circuits from pulses and power spikes as well as a wide range of test and measurement applications. Mini-Circuits has developed different types of high frequency, high accuracy power detectors for these applications. These power detector designs have overcome design challenges at mmW frequencies to enable product features that provide market-leading performance for the price point. These design challenges include improving the input and output matching of the detectors over a wide frequency range in the specified product housing that enables extended dynamic range performance over the operating frequency range compared to competitive models. This article will provide an overview of the different types of power detectors and some of the common applications each is best suited for. Specific use cases for measurement setups will be also presented for each type of detector.