Dual-frequency, electronically steerable, mm-wave, phased array antenna using mmic technology

Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple- scanning beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. In this paper, current developments in GaAs MMIC technology are described,and the status and prospects of the technology are assessed.

Modern reconfigurable communication systems demand microwave voltage-controlled oscillators (VCOs) possessing an octave-wide bandwidth. Many advanced applications require also a low phase noise and a low current consumption for such VCOs. To meet an octave-bandwidth specification in combination with a low phase noise and a low current consumption it is desirable to implement a microwave monolithic integrated circuit (MMIC) technology. In-house gallium arsenide (GaAs) MMIC technology is implemented to build VCOs in this work. At the same time, in order to achieve a high-Q wide frequency tuning range, we implemented also a discrete variable capacitance diode (varicap). The discrete varicap is stacked above MMIC oscillator chip. A vertical design structure of the discrete varicap guarantees a high overlap capacitance ratio (K>20) along with reduced affect of the parasitic reactance. A high overlap capacitance ratio is needed for an octave-wide frequency tuning, while reduced affect of the parasitic reactance increases Q-factor of the VCO resonator. Hence, a sequential integration of the discrete varicap over monolithic oscillator chip resolves referred tough challenges in the design of VCO. Integrated VCO is finally packaged as a surface-mount device (SMD). At that SMD ceramic package is sealed with the metal lid. The oscillator circuitry is based on the conventional negative resistance approach with a positive feedback realized by common-source capacitance. An active element of the oscillator is a pseudomorphic high electron-mobility transistor (pHEMT). The gate length of a transistor is 0.15 µm. The width of the gate varies from 240 µm to 360 µm depending on working frequencies of the VCO. The varicap is built on the GaAs epitaxial heterostructure having customized gradient doping profile with abrupt junction. Nonlinear behavioral model of the varicap is extracted from the diode measurements and is further used for VCO simulation. Two types of VCO have been designed, fabricated and tested. First (second) type of VCO provides a tuning range from 5 to 10 GHz (from 10 GHz to 20 GHz), respectively. The measurement results demonstrate an output power of 3.9 dBm; a current consumption of 30 mA at a supply voltage of 5 V; a phase noise of minus 90 dBc/Hz at 100 kHz offset (minus 85 dBc/Hz at 100 kHz offset) for the first (second) type of VCO, respectively.

Rapid expansion of microwave systems in phased array radar and commercial applications in the emerging wireless communication system areas requires affordable, compact, lightweight, reliable, solid state, integrated microwave transmit/receive (T/R) modules. Traditional microwave modules fabricated using microstrip-based hybrid/ monolithic integrated circuitry are incompatible with low cost, high volume, robotics manufacturing techniques for multi-chip microwave modules, because of the fragile nature of current 4 mil-thick gallium arsenide monolithic microwave integrated circuits (MMICs). Backside processing, including wafer thinning and via-hole ground electrode access, are also significant yield limiting factors for MMIC manufacturing. Hughes has developed a novel, robust, flip-chip approach for microwave T/R modules using self-aligned, solder reflow, multichip assembly techniques. The rugged (25 mil thick), passivated MMIC chips with coplanar waveguide circuitry, silicon-like, on-chip multilayer metal interconnects, with off-chip plated metal electrical/thermal paths offers major advantages over conventional MMICs (Table 1). Elimination of wafer thinning will be critical for processing and handling of large-diameter wafers. The use of plated metal thermal bumps directly on top of active circuit elements leads to 30% thermal property improvement over conventional GaAs MMICs.

Recent progress of GaAs Monolithic Microwave Integrated Circuit (MMIC) and Gb/s logic has established a solid foundation for many future system applications. Systems benefiting from these advances include phased/adaptive arrays, MILSATCOM, Television Receive-Only (TVRO) receiver, Electronic Warfare (EW), instrumentation and radar. This paper presents various MMIC technologies and tradeoffs of materials (crystal growths, orientations, material properties, characterization techniques, etc.), processes (ion-implantation, Molecular Beam Epitaxy, Vapor Phase Epitaxy, Liquid Phase Epitaxy), and circuit fabrication via hole, air bridge, active matching, etc. The performance of the presently achieved SHF/EHF MMIC's are summarized. Technical problems, possible solutions, and future trends of MMIC design and fabrication (impedance matching methods, bias, low noise techniques, medium power IC's, EHF circuits, filters, isolators, packaging techniques, etc.) are also described.

A 64-element, Ku-band, active phased-array antenna developed for application in communications satellites is presented. Antenna radiation pattern and spatial isolation measurements show good agreement with predictions. In order to minimize the performance variations among the array elements, the 5-b digital phase shifter, the 50-b digital attenuator, and the amplifiers have been realized using MMIC (monolithic microwave integrated circuit) technology. This allowed the realization of 64 active modules whose amplitude and phase variations over 11.7 to 12.7 GHz are within +or-1.5 dB and +or-10 degrees . The successful development of this broadband active phased array has demonstrated the maturity of MMIC technology and the feasibility of active arrays in future communications satellites. >

This paper presents the design and measured results of a high-performance, miniature 6-/4-GHz receiver for on-board satellite applications. The receiver has a gain of 76 dB, weighs less than 500 g, and consumes less than 5 W of DC power. Extensive use is made of custom-designed monolithic microwave integrated circuit (MMIC) chips for all RF functions, to achieve a high level of reliability and miniaturization. A pseudomorphic high-electron-mobility transistor (p-HEMT) C-band low-noise amplifier with 40-dB gain and a room temperature minimum noise figure of approximately 0.85 dB is used in the front end. Gain adjustments are provided in l-dB steps at IF frequency between 3.5 and 4.5 GHz.

메타 물질의 한 형태인 LHTL(Left-Handed Transmission Line)과 기존의 전송 선로 형태인 RHTL(Right-Handed Transmission Line)을 이용하여 광대역 I-Q 벡터 신호 생성을 위한 <TEX>$90^{\circ}$</TEX> 커플러를 설계, 제작하고 측정을 하였다. LHTL과 RHTL 모두 커패시터와 인덕터를 이용하여 합성 전송 선로 형태로 구성함으로써, 그 크기를 최소화 하였다. 또한, 제안된 커플러 제작에 필요한 Wilkinson 전력 분배기를 합성 RHTL을 이용하여 간단하게 구현함으로써 전체 회로의 크기를 <TEX>$11mm{\times}12mm$</TEX>로 만들 수 있었다. 주파수 범위 0.8~1.25 GHz에 대해 출력의 위상 차이가 <TEX>$90^{\circ}{\pm}5^{\circ}$</TEX>를 유지함으로써 광대역 <TEX>$90^{\circ}$</TEX> 커플러를 작은 크기로 만들 수 있었다. 동 주파수 범위에 대해 삽입 손실을 1.6 dB 이하로, 반사 손실을 10.1 dB 이상으로 유지 가능했다. 필자가 아는 한 이는 그 주파수 대에서 가장 작은 광대역 <TEX>$90^{\circ}$</TEX> 커플러이며, MMIC(Monolithic Microwave Integrated Circuit)로 만들 경우 그 크기를 훨씬 더 줄일 수 있을 것이다. By using LHTL(Left-Handed Transmission Line) which is a form of a metamaterial and conventional RHTL (Right-Handed Transmission Line), we designed, fabricated and tested a broadband <TEX>$90^{\circ}$</TEX> coupler which is a basic circuit for I-Q vector signal generation. Synthetic LHTL and RHTL were implemented with capacitors and inductors only, that the size is minimized. Also, by implementing a Wilkinson power divider which is required for the suggested circuit using a synthetic RHTL, the size of whole circuit is only <TEX>$11mm{\times}12mm$</TEX>. For the frequency range 0.8~1.25 GHz, the phase difference at the outputs maintained <TEX>$90^{\circ}{\pm}5^{\circ}$</TEX> and thus, a broadband <TEX>$90^{\circ}$</TEX> coupler could be made in a compact form. for the same frequency range, the insertion loss is less than 1.6 dB and return loss is more than 10.1 dB. To the best of our knowledge, this is the smallest and broadband <TEX>$90^{\circ}$</TEX> coupler for the frequency range and if the circuit is made with MMIC(Monolithic Microwave Integrated Circuit) technology, the size will be reduced much further.

A 94-GHz phased array antenna using a log-periodic antenna has been developed on a GaAs substrate. The developed phased array antenna comprises four log-periodic antennas, a phase shifter, and a Wilkinson power divider. This antenna was fabricated using the standard microwave monolithic integrated circuit (MMIC) process including an air bridge for unipolar circuit implementations on the same GaAs substrate. The total chip size of the fabricated phased array antenna is 4.8 mm × 4.5 mm. Measurement results showed that the fabricated phased array antenna had a very wide band performance from 80 GHz to 110 GHz with return loss characteristics better than -10 dB. In the center frequency of 94 GHz, the fabricated phased array antenna showed a return loss of -16 dB and a gain of 4.43 dBi. The developed antenna is expected to be widely applied in many applications at W-band frequency.

In this paper, we have first proposed a RF MEMS thermistor power sensor based on Wheatstone full-bridge structure. The proposed RF MEMS thermistor power sensor is fabricated using GaAs MMIC (monolithic microwave integrated circuit) technology. In this device, two parallel low TCR (temperature coefficient of resistance) heaters are employed to keep the impedance match stable. And a Wheatstone full-bridge formed by four identical thermistors is used for the unknown RF power measurement. To improve the sensitivity of the sensor, a MEMS substrate membrane is fabricated beneath the hot area to suppress longitudinal heat loss by back etching process. The whole structure is integrated with CPW transmission line, which has the potential of high integration density. Compared with traditional thermistor power sensor, this device has both advantages of stable impedance match and high sensitivity.

Design of a compact multilayer circularly polarized phased array transmit antenna system for satellite applications

This paper discusses NASA Lewis Research Center's program for development of monolithic microwave integrated circuits (MMIC) for application in space communications. Emphasis will be on the improved performance in power amplifiers and low noise receivers which has been made possible by the development of new semiconductor materials and devices. Possible applications of high temperature superconductivity for space communications will also be presented.

A low noise free-running Dielectric Resonator Oscillator based on AlGaAs/GaAs HBT compatible to MMIC (Monolithic Microwave Integrated Circuit) has been designed and simulated. The design uses a HBT with f/sub T/ in 71 GHz, and low flicker noise in Ka band. Large signal analysis of the oscillator is based on harmonic balance method, and simultaneous signal and noise method has been applied to calculate output phase noise spectrum. The designed circuit oscillates at 28.225 GHz with output power of 9.29 dBm. The phase noise of stable oscillator has been determined to be -116 dBc/Hz and -127 dBc/Hz at 100 kHz and 1 MHz off carrier, respectively.

A design of 18 - 20 GHz GaAs Monolithic Microwave Integrated Circuit (MMIC) 4-bit phase shifter is presented. The phase shifter adopts high-pass/low-pass type and switched filter networks. The passive HEMTs are used as key components for controlling the phase shift. All the drain and source terminals are DC grounded while the gates are applied with 0 V or −3 V. The power consumption is almost zero. The phase shifter obtains 9 ± 1 dB insertion loss and the input and output return losses are higher than 9.8 dB over the 18 - 20 GHz bandwidth of interest. The phase resolution is 22.5° with the root mean square (RMS) phase error is less than 5° within the bandwidth. The phase shifter is designed by using GaAs 0.15 µm process. The chip area is very compact, just about 2 mm ×1 mm, including all the pads.

Design and development of a 14.25 GHz to 57 GHz frequency quadrupler has been presented in this paper using GaAs/InGaAs/AlGaAs based pseudomorphic High Electron Mobility Transistor (pHEMT) in a single-stage, Monolithic Microwave Integrated Circuit (MMIC). Fabricated MMIC chip has achieved 5.2 dB of conversion loss at 57 GHz for 0 dBm of input power at 14.25 GHz. Saturated output power is −4.5 dBm without any output amplifier stage. Fractional bandwidth has been obtained as 7%, while output power variation is within 5 dB. DC power consumption of the circuit is only 60 mW. Fundamental and other unwanted harmonic rejection is in excess of 25 dBc. Highly stable and high quality output spectrum of the frequency quadrupler makes it suitable for Millimeter Wave (MMW) transceiver application.

In this article, we present the design and fabrication of a monolithic microwave‐integrated circuit (MMIC) using 0.13‐μm complementary metal‐oxide‐semiconductor (CMOS) radiofrequency (RF) process for a low‐noise amplifier (LNA) and a passive down mixer for a microwave Doppler sensor receiver operating in the 24‐GHz band (K band). The low‐noise amplifier uses a single‐stage cascode structure to ensure a small size and gain suitable for a microwave Doppler sensor. The down mixer has a passive frequency mixer structure and a single balanced design using balun for the local oscillator (LO) input. The output of the LNA and the input of the down frequency mixer are conjugately matched to minimize the flicker noise generated by the receiver for the microwave Doppler sensor. The designed MMIC showed a voltage conversion gain of 14.46 dB and an input P1dB of −21.16 dBm when the LO power was 0 dBm within the IF range (0.01‐1 GHz). A noise figure of less than 19.24 dB was obtained. The MMIC area and the power consumption were 0.647 × 0.363 mm2 and 6 mW, respectively.