GaAs MMIC Chip Research Articles

Liquid–Metal Vertical Interconnects for Flip Chip Assembly of GaAs C-Band Power Amplifiers Onto Micro-Rectangular Coaxial Transmission Lines

Prior work has demonstrated a new process utilizing room-temperature liquid metal, Galinstan, as an interconnect material for flip-chip bonding. This interconnect forms a flexible bond between chips and carriers, and, therefore, a flip-chip assembly using this technology is much less susceptible to thermomechanical stresses. This paper applies this concept to interconnect GaAs MMIC chips to 3-D Polystrata transmission-line structures. Passive assemblies are utilized to model, test, and verify liquid-metal interconnections, giving average losses per liquid-metal transition of about 0.11 dB out to 26.5 GHz, low parasitics per transition, and demonstrated reliability after temperature cycling. A prefabricated GaAs MMIC chip is postprocessed for liquid-metal assembly. Measured results show, over the MMIC's 4.9-8.5-GHz frequency range, the system's overall reduction in gain of the MMIC is 1.4 dB or 0.7 dB per RF transition as compared with direct probing of the MMIC chip.

71–86 GHz antenna–MMIC interface using stacked patch configuration

A stacked patch configuration is used to electromagnetically couple a GaAs MMIC chip to a patch antenna integrated in the lid of the MMIC package. The lid is formed using a liquid crystal polymer substrate. Presented is the first implementation that covers the E-band frequency range from 71–86 GHz for long-range wireless communications. Antenna gain is greater than 8 dBi using a short horn with straight sidewalls.

New MMIC's for tuners in multichannel video distribution systems using optical fiber networks

New MMIC's have been developed for an ultra-broadband FM video tuner in a multi-channel video distribution system using optical fiber networks. The MMIC's provide both frequency synthesis and up-conversion. They are integrated on two GaAs MMIC chips and one Si LSI chip. The chips are mounted in a flat package to form a tunable block up converter, By combining the MMIC's with currently available consumer product type components, a low cost FM video tuner with a 2 GHz tuning bandwidth was achieved in hardware. Successful tuning performance is obtained over the whole tuning frequency range. >

High-speed, 100+W RF switches using GaAs MMICs

A low-loss, inductive gate bias network structure which allows a very high stacking level of FET devices for high-power RF switching applications is reported. The design, implementation, and performance of S- and C-band SPDT switches based on this structure are described. Multiple GaAs MMIC chips integrated into a suspended-substrate hybrid circuit are used. At S-band, switch risetimes/falltimes of less than 40 ns and an RF power handling capability of 300 W CW have been demonstrated. This input signal level could be maintained during the switch state transitions (hot-switching), while being switched between the two output ports at rates of up to 500 kHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

GaAs MMIC's for Digital Radio Frequency Memory (DRFM) Subsystems

A DRFM analog subsystem using ten GaAs MMIC chips (six limiting amplifiers, one quadrature down-converter, two IF amplifiers, and one quadrature up-converter) has been developed and integrated into a 0.72-cubic-inch module. The 2-6-GHz limiting amplifier provides 12 dBm constant output power, the quadrature IF mixer down-converts a 2-6-GHz input signal into two 1 MHz to 1 GHz quadrature IF signals, the IF amplifier provides the required gain, and a quadrature up-converter converts the IF signals to a 6-8-GHz output band. The input signal dynamic range is 50 dB. The amplitude and phase tracking performance of the two IF channels is +-0.5 dB and +-5°, respectively. The output signal is a single-sideband suppressed carrier signal. The sideband rejection is 20 dB and the LO to RF isolation is 27 dB.