John M. Golio

Projected frequency limits of GaAs MESFETs

Limits to the ultimate frequency performance which can be realized with GaAs MESFETs have been projected. These predictions are based on the reported performance of 137 devices fabricated between 1966 and 1988 and on first-order modeling. The predictions indicate that ultimate maximum frequency of oscillation values may approach 700 GHz, while gain-bandwidth product values as high as 200 GHz may be realized. >

Simulation of optically injection-locked microwave oscillators using a novel SPICE model

Optical injection-locking of GaAs field-effect transistor microwave oscillators has been examined experimentally as well as by using two different optical interaction models. An additional simulation program with IC emphasis (SPICE) circuit for observing small locking ranges is also described. This first-order interaction model which utilizes a standard version of SPICE produces predictions of injection-locking range in excellent agreement with measured results. These tools allow the oscillator designer to optimize the injection-locking performance by analyzing various circuit topologies and DC bias levels. >

A highly integrated two channel MMIC down converter with gain control

A complete MMIC (monolithic microwave IC) down converter with variable-gain control has been fabricated. A 6-8-GHz RF input signal is converted using a fixed 10-GHz LO (local oscillator), to a two-channel 2-4-GHz IF. The die is highly integrated, including an RF preamplifier, a double-balanced mixer, an LO amplifier, a power divider, IF amplification, and two voltage-controlled IF amplifiers which provide variable-gain adjustment. Back vias are utilized to establish grounding for both DC and RF. Probe pads are also included for measuring chip-level performance. A circuit description, the design techniques, and measured performance results are presented.<<ETX>>