Monolithic Microwave Integrated Circuit Technology Research Articles

Lester Eastman and the Monolithic Microwave Integrated Circuit Technology [Speaker’s Corner

Lester Eastman and the Monolithic Microwave Integrated Circuit Technology [Speaker’s Corner

Compact hand-guided 3D scanning terahertz sensor platforms with 3D-printed aspherical telecentric f-θ lens

AbstractWe report on the development of a handheld three-dimensional (3D) terahertz scanning system with an aspherical telecentric 3D-printed f-θ lens using selective laser sintering. The lens covers a broader scan line of 50 mm with its larger aperture, compared to the 20 mm range in our initial work, which was presented at the European Microwave Week 2021. In order to evaluate the adaptability of the optomechanical components with different sensor units, two different integrated frequency-modulated continuous wave radar modules based on monolithic microwave integrated circuit technology, operating in W- and D-bands are tested within the measurement scheme. The optomechanical part consists of a galvanometer scanner mirror and the f-θ lens. The optical system enables B-scans perpendicular to the manual translational movement of the sensor unit by its user. An integrated guiding wheel system with rotary encoder makes it possible to correlate the measurement points to their respective locations, enabling complete 3D volumetric inspection of the corresponding structures, which is particularly useful for the inspection along cracks and welds.

Theoretical and Experimental Investigations of an Integrated Microwave Power, Frequency, and Phase Detector for X-Band Applications

In this article, we present an integrated microwave power, frequency, and phase detector by GaAs monolithic microwave integrated circuits technology. The novelty of the reported detector is carefully designed by cascading a micromachined six-port coupler, a power divider, three power combiners, and four thermoelectric power sensors to realize microwave power, phase, and frequency detection. Compared with previous study, the reported microwave integrated detector has a more compact design and high-power-handling capacity. The advantage of the proposed technique is that the three parameters (power, frequency, and phase) of microwave signals are directly measured via the output of the thermovoltage. This makes the integrated microwave detection system more suitable for systems with complex requirements, such as radar systems. The experimental results demonstrate that the output thermovoltage and incident microwave power exhibit good linearity over a dynamic range of 0.1–1000 mW. Also, the measured sensitivities are 22.9, 27.2, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$33.7~\mu \text{V}$ </tex-math></inline-formula> /mW at 8, 10, and 12 GHz, respectively. A new method based on phase comparison is proposed for frequency detection. Also, the measured sensitivity is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.42~^{\circ }$ </tex-math></inline-formula> /GHz over <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${X}$ </tex-math></inline-formula> -band. By introducing the reference signal, the function of phase detection is achieved based on the principle of vector synthesis over a dynamic range of 0°–360°. Also, the measured sensitivity is better than 98.38 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{V}$ </tex-math></inline-formula> /° at 500 mW. Furthermore, an integrated detection model is also proposed based on the microwave network analysis. The experimental results agree well with the proposed model. The results would be beneficial to improve future microwave integrated detector designs.

Ultra‐miniaturised C ‐band power divider using capacitive loading and defect grounded structures

This article reports a compact Power Divider design employing a combination of a capacitive load and Defect Grounded Structures (DGS) on GaAs substrate for MMIC technology in the C band. The integration of these two techniques offers a compact power divider with a decrease in quarter-wave transmission line length from λ/4 to λ/16 and harmonic suppression up to 50 GHz. Capacitive loading reduces the size, and DGS improves harmonic suppression and further decreases the size of the structure. The designed power divider is simulated in Ansys HFSS 19.2 and provides a return loss of 25.66 dB, with an insertion loss of 3.01 dB at 5.4 GHz and isolation of 13.37 dB. Isolation is further improved to 30.89 dB using a parallel combination of resistor and capacitor in the isolation network. The prototype of the proposed circuit has been fabricated using RT/duroid® 5880 as substrate. Measurement results show insertion loss and return loss of 3.02 and 23.46 dB. Isolation of 22.43 dB was achieved. The proposed design provides a size reduction of 73.7% with harmonic suppression up to 10th harmonics by 10 dB, making it suitable for high-performance monolithic microwave integrated circuits (MMIC).

Design and Implementation of Phase Shifter for Wireless Communication

Abstract: Phase shifters are common microwave devices that are widely used to control the phase of a microwave signal in mobile satellite systems, microwave instrumentation and measurement systems, modulators, noise cancellation systems, frequency converters, electronic beam scanning phase arrays, microwave imaging, and many other industrial applications is used for. Phase shifters are passive devices used to perform variable phase changes in the wave propagating through it. Phase shifters require compact size, low cost and low insertion loss in the desired bandwidth. The size of the phase shifters is a crucial parameter, especially in the design of portable microwave devices, due to the space constraints. The significantly higher insertion loss of phase shifters used in a transmitter causes a significant reduction in transmitting power levels, while it causes a severe drop in signal to noise ratio when the phase shifter is a part of the receiver.. Phase shifters are essential components in phased array antennas for wireless and Radio Detection And Ranging (RADAR) applications. Loaded line phase shifter, reflective line phase shifter and switched line phase shifters are the most commonly used. The electrical performance of a phase shifter is specified in terms of insertion loss, phase error, operating bandwidth and power handling capacity.. Emerging wireless systems have transceivers that require compact and cost effective phase shifters. Physical size and weight of phase shifters are the major issues in mobile and the wireless applications. Therefore, miniaturization of phase shifters has become an important objective of radio frequency (RF) designers to provide portability and affordability in wireless/mobile systems. The present research work mainly focuses on planar phase shifter design with linear phase shift. In this a Defected Ground Structures (DGS) is proposed where as ,Monolithic Microwave Integrated Circuits (MMIC), Micro Electro Mechanical Systems (MEMS) and fractals have emerged as the possible techniques for miniaturization of RF systems and antennas. However the existence of defected cells on the ground plane may limit the use of DGS based phase shifters. MMIC technology increases the cost and complexity of manufacturing whereas MEMS based phase shifter is prone to limited life and yield. In this thesis, fractal techniques are adapted to design and develop miniaturized phase shifters for wireless applications.

Multisection Ultra-Broadband Directional Coupler Designed in MMIC Technology

An ultra-broadband multisection directional coupler designed in Monolithic Microwave Integrated Circuit (MMIC) technology has been presented. It has been shown for the first time that it is possible to achieve bandwidths exceeding one frequency decade, simultaneously taking under account technological constrains. The proposed directional coupler is composed of three coupled-line sections having different values of electrical lengths and coupling coefficients. The strongest coupled section has been designed as an asymmetric three-strip coupled-line section, whereas the rest of the sections have been implemented as symmetric two-strip coupled-line structures. To improve electrical performance of the coupler, a compensation method has been implemented together with loss analysis which has to be considered in lossy inhomogeneous medium. The proposed 3-dB directional coupler has been designed in PH25 process based on gallium arsenide (GaAs) from United Monolithic Semiconductors (UMS), and fabricated. The measurement confirms applicability of the design method in monolithic technology for such networks operating in bandwidth exceeding one frequency decade.

A $W$ -Band SSPA With 100–140-mW $P_{\text{out}}$ , &gt;20% PAE, and 26–30-dB $S_{21}$ Gain Across 88–104 GHz

We report a three-gain-stage 88–104-GHz $W$ -band solid-state power amplifier (SSPA) monolithic microwave integrated circuit (MMIC) having modest 100–140-mW output power ( $P_{\mathrm {out}}$ ), high gain, and high power-added efficiency (PAE). The MMIC technology is 250-nm InP HBT. PA $S_{21}$ gain is 29.5 dB with ±0.5-dB variation. PA 3-dB $S_{21}$ gain roll-off is between 88 and 104.5 GHz with high $\vert S_{11}\vert $ and $\vert S_{22}\vert $ return losses. DC power ( $P_{\mathrm {dc}}$ ) is 0.41 W. Across 88 –104 GHz, the PA-saturated output power $P_{\mathrm {sat}}$ is 100–120 mW with greater than 20-dB power gain and 20% PAE. At 92 GHz, peak 120-mW $P_{\mathrm {out}}$ with 20-dB gain and 24.7% PAE is demonstrated. $P_{\mathrm {out}}$ at 1-dB gain compression OP $_{\mathrm {1-dB}}$ is estimated to be 15–17 dBm. At 94 GHz and an elevated output stage bias (0.50-W $P_{\mathrm {dc}}$ ), 140-mW $P_{\mathrm {out}}$ with 20-dB gain and 24.4% PAE is demonstrated. This work contributes to and improves the state of the art for $W$ -band PAs in the simultaneous performance areas of power, gain, and PAE.

X-Band Monolithic Microwave Integrated Detector Based on MEMS Thermoelectric Power Sensor

This letter reports an X-band monolithic microwave integrated detector based on MEMS thermoelectric power sensor. It is fabricated by the GaAs monolithic microwave integrated circuit technology. The novelty of the proposed device is that it can achieve the integrated detection of the microwave signal (power, frequency, and phase) in a broad frequency bandwidth. The proposed integrated detector consists of three parts: power detection/AM demodulation; frequency detection; and phase detection, which are finally integrated on a single chip by several dual-band power dividers. In this letter, the designed dual-band power dividers have excellent impedance matching properties on X-band (8–12 GHz). The parameters to be tested are all converted into output thermal voltages by the terminated thermoelectric power sensors. Measurement results show good return loss and isolation on X-band. Power detection, AM demodulation, frequency detection, and phase detection have all been tested effectively.

LINC Method for MMIC Power Amplifier Linearization

Background: This article proposes the design and implementation of a MMIC (monolithic microwave integrated circuits) Power amplifier using the ED02AH process. Methods: The MMIC ED02AH technology have been developed specifically for microwave applications up to millimeter waves, and for high-speed digital circuits. The use of a single branch of a power amplifier can produce high distortion. In the present paper, the Linear amplification with nonlinear components (LINC) method is introduced and applied as a solution to linearize the power amplifier, it can simultaneously provide high efficiency and high linearity. To validate the proposed approach, the design and characterization of a 5.25 GHz LINC Power Amplifier on MMIC technology is presented. Results: Good results have been achieved, and an improvement of about 37.50 dBc and 59 dBc respectively is obtained for the Δlower C/I and Δupper C/I at 5.25 GHz. Conclusion: As a result of this method, we can reduce the Carrier Power to Third-Order Intermodulation Distortion Power Ratio. Excellent linearization is obtained almost 37.6 dBc for Δlower C/I and 58.8 dBc for Δupper C/I.

Modeling of Multilayer MMIC Coplanar Waveguide Low Pass Filter for Cellular Application

In the early development of Monolithic Microwave Integrated Circuit (MMIC) technology, most of the components use Microstrip structure. In order to connect the active components to the ground in the Microstrip design is limited by the thickness of the substrate to avoid circuit performance degradation due to vertical coupling. Thus it can be said that the Microstrip is not the primary choice of design in operating components at microwave and millimeter wave frequencies. The Coplanar Waveguide (CPW) design technique was proposed as an alternative to the Microstrip structure for MMIC components. With CPW design technique, it generates components and circuits which are cost-effective and allow miniaturization of components in MMIC environment. In this paper, CPW Low Pass Filter (LPF) electromagnetic modeling has been demonstrated based on multilayer MMIC technology for the 2,100 MHz mobile application. The LPF CPW specification has been modeled with the substrate of GaAS (εr=12.9) and Polymide (ϵr=3.7). The thickness of GaAS substrate and Polyimide dielectric is 600 micron and 2.5 micron respectively for each layer.

Bent cantilever radio frequency microelectromechanical system power detector with improved linearity up to 1 W

This study reports a bent cantilever radio frequency microelectromechanical system power detector with improved linearity up to 1 W. The proposed device employs an upward bent cantilever for power detection. The novelty of this structure is that the bend of this kind in cantilever can realize the compensation for non-linear saturation at high power level effectively. As a result, the linearity will be improved on the condition of high power detection. An equivalent circuit model of mechanical principle is established to analyse the bent cantilever behaviour. The whole device is fabricated using GaAs microwave monolithic integrated circuit technology. The bent cantilever is constructed to overcome the stress gradient during deep etching releasing process. Measurement results prove the improved linearity from 100 mW to 1 W and the corresponding sensitivity is 2.8 aF/mW at 10 GHz.

A Micro-Machined Phase Discriminator With Improved Power Capacity on C-Band and X-Band

This paper reports a micro-machined phase discriminator with improved power capacity on C-band and X-band. The proposed phase discriminator is processed using GaAs microwave monolithic integrated circuit technology. First, a dual-frequency power combiner is designed to extend the working frequency band. Second, a sandwich-type thermoelectric power sensor is adopted to improve the power capacity. The unique device consequently has the advantages of ultra-wide band and high power capacity. The measurement results show good S-parameters within 6-12 GHz. The sensitivities among all measured frequency points are better than 42.3 μV/deg at 23 dBm, 82.5 μV/deg at 27 dBm, and 167.3 μV/deg at 30 dBm, respectively. What is more, the experiment of response time shows that the rise time is about 617.25 μs, while the fall time is about 304.69 μs.

Evolution of the Nonuniform Distributed Power Amplifier: A Distinguished Microwave Lecture

The emergence of gallium nitride (GaN) monolithic microwave integrated circuit (MMIC) technology has been a real game-changer for high-power amplifier and control components. When compared with the incumbent gallium arsenide (GaAs) MMIC technology, a near order of magnitude increase in output power and power handling was achieved with similar efficiency, noise, and frequency capability. In addition, GaN transistors epitaxially grow on high-thermal conductivity substrates such as silicon or silicon carbide (SiC), helping to mitigate some thermal issues associated with highoutput power density.

Analysis of Lateral Thermal Coupling for GaN MMIC Technologies

This paper presents a study of the lateral heat propagation in an aluminum gallium nitride/gallium nitride (AlGaN/GaN) heterostructure grown on a silicon carbide substrate. The study is enabled by the design of a temperature sensor that utilizes the temperature-dependent $I$ – $V$ characteristic of a semiconductor resistor, making it suitable for integration in GaN monolithic microwave integrated circuit technologies. Using the sensor, we are able to characterize the thermal transient response and extract lateral thermal time constants from the measurements. Time constants in the range from 25 $\mu \text{s}$ to 1.2 ms are identified. Furthermore, the heat propagation properties are characterized for heat source-to-sensor distances of 86– $484~\mu \text{m}$ , resulting in delay times from 3.5 to $111~\mu \text{s}$ . It is shown that both the time constants and propagation delay increase with temperature. An empirical model of the sensor current versus temperature and voltage is proposed and used to predict the junction temperature of the sensor. The study provides knowledge for heat management design and proposes an integrated temperature measurement solution for future highly integrated GaN applications.

DC-25 GHz and Low-Loss MEMS Thermoelectric Power Sensors with Floating Thermal Slug and Reliable Back Cavity Based on GaAs MMIC Technology.

Wideband and low-loss microwave power measurements are becoming increasingly important for microwave communication and radar systems. To achieve such a power measurement, this paper presents the design and measurement of wideband DC-25 GHz and low-loss MEMS thermoelectric power sensors with a floating thermal slug and a reliable back cavity. In the sensors, the microwave power is converted to thermovoltages via heat. The collaborative design of the thermal slug and the back cavity, i.e., two thermal flow paths, is utilized to improve the efficiency of heat transfer and to ensure reliable applications. These sensors are required to operate up to 25 GHz. In order to achieve low microwave losses at the bandwidth, the floating thermal slug is designed instead of the grounded one. The effects of the floating slug on the reflection losses are analyzed by the simulation. The fabrication of these sensors is completed by GaAs monolithic microwave integrated circuits (MMIC) and micro-electro-mechanical systems (MEMS) technology. Measured reflection losses are less than −25.6 dB up to 12 GHz and −18.6 dB up to 25 GHz. The design of the floating thermal slug reduces the losses, which is equivalent to improving the sensitivity. At 10 and 25 GHz, experiments exhibit that the sensors result in sensitivities of about 51.13 and 35.28 μV/mW for the floating slug and 81.68 and 55.20 μV/mW for the floating slug and the cavity.

Electromagnetic Modelling of MMIC CPWs for High Frequency Applications

Realising the theoretical electrical characteristics of components through modelling can be carried out using computer-aided design (CAD) simulation tools. If the simulation model provides the expected characteristics, the fabrication process of Monolithic Microwave Integrated Circuit (MMIC) can be performed for experimental verification purposes. Therefore improvements can be suggested before mass fabrication takes place. This research concentrates on development of MMIC technology by providing accurate predictions of the characteristics of MMIC components using an improved Electromagnetic (EM) modelling technique. The knowledge acquired from the modelling and characterisation process in this work can be adopted by circuit designers for various high frequency applications.

C-Band Single-Chip Radar Front-End in AlGaN/GaN Technology

This paper presents the design and measurement results of a single-chip front-end monolithic microwave integrated circuit (MMIC), incorporating a high-power amplifier, transmit–receive switch, low-noise amplifier, and calibration coupler, realized in 0.25 $\mu \text{m}$ AlGaN/GaN-on-SiC MMIC technology of UMS (GH25-10). The MMIC is operating in C-band (5.2–5.6 GHz) and is targeting the next generation spaceborne synthetic aperture radar. The use of GaN technology has resulted in a design that is robust against antenna load variation in transmit as well as against high received power levels, without the need for an additional limiter. By including a transmit-receive switch on the MMIC there is no need for an external circulator, resulting in a significant size and weight reduction of the transmit–receive module. The measured output power in transmit is higher than 40 W with 36% PAE. The receive gain is higher than 31 dB with better than 2.4 dB noise figure. To the best of the author’s knowledge this is the first time such performance has been demonstrated for a single-chip implementation of a C-band transmit–receive front-end.

Ka‐band RF MEMS capacitive switch with low loss, high isolation, long‐term reliability and high power handling based on GaAs MMIC technology

This study presents a Ka-band radio frequency (RF) micro electro mechanical systems (MEMS) capacitive switch with low loss, high isolation, long-term reliability and high power handling based on GaAs microwave monolithic integrated circuit (MMIC) technology. In this design, a T-matching structure is employed to realise impendence matching at ‘up-state’ by modifying the dimensions of centre signal line. Thus, the reflection loss and insertion loss are improved effectively. Measurement results show that in ‘up-state’ position, the input reflection coefficient (S11) is less than −20.4 dB with the forward transmission coefficient (S21) of better than −0.27 dB at Ka-band (27–40 GHz). At ‘down-state’, the switch is designed in a state of self-resonance to obtain high isolation. The measured isolation is better than 20 dB over Ka-band and can reach 35 dB at its self-resonant frequency of 35 GHz. The measured actuation voltage is about 36 V. The measured lifetime is at least 5.76 × 107 cycles. The measured power handling capability can reach up to 39 dBm. The proposed compact RF MEMS capacitive switch possesses excellent performances in terms of low insertion loss, high isolation, long lifetime and high power handling capability.

A Four-Port Microwave Phase Detector at $X$ -Band Based on MEMS Power Sensors

A four-port microwave phase detector based on MEMS power sensors at $X$ -band (8–12 GHz) is proposed in this paper. It consists of two power dividers, two power combiners, two phase shifters, and two MEMS power sensors. Four power dividers/combiners and two phase shifters compose a four-port junction to expand the phase detection range. A thermoelectric power sensor and a capacitive power sensor compose the MEMS power sensor for low and high power measurement. Two types of power sensors can improve the measurement range and enhance the overload capacity. This microwave phase detector is fabricated by GaAs monolithic microwave integrated circuit technology. Experiments show that its return loss is better than −10 dB, and the isolation is better than −13.2 dB over $X$ -band. Measured results of the phase shift fit well with the calculated results in an entire cycle of −180°~+180°. The phase detection sensitivities are $16.62~\mu \text{V}$ /° and 23.94 aF/°, and the response times are 0.408 ms and less than 20 ms for the two types of sensors, respectively. The dynamic range of phase detector can be expanded up to 4 W, which is almost quintuple our previous works.

Thermal Influence on Multibias Small- and Large-Signal Parameters of GaAs pHEMT Fabricated in Multilayer 3-D MMIC

Temperature influence on the device behavior has been carried out on AlGaAs/InGaAs/GaAs-based pseudomorphic high-electron mobility transistor fabricated in multilayer 3-D monolithic microwave integrated circuits technology over multibias operation condition. The multibias thermal effect on the dc and RF, small-signal (up to 40 GHz) and large-signal parameters, including the third-order intercept points as well as the linear and third-order intermodulation output power performance at 4 GHz were analyzed and reported for the first time. In addition, the noise figure parameters of device have been reported and estimated at 10 GHz. The temperature coefficients of the device dc and RF parameters are carefully established at the peak transconductance condition. The results are important for the design optimizations of advanced monolithic multilayer integrations.