The recent trend in modern information technology has been towards the increased use of portable and handheld devices such as cellular telephones, personal digital assistants (PDAs), and wireless networks. This trend presents the need for compact and power efficient radio systems. Typically, the most power inefficient device in a radio system is the power amplifier (PA). PA inefficiency require...

-In this work we present a 100-MESFET oscillator which gives 21 W of CW effective radiated power (ERP) with a 16 dB directivity and a 20% dc to RF conversion effciency at 5 GHz. The oscillator is a planar grid structure periodically loaded with transistors. The grid radiates and the devices combine quasi-optically and lock to each other. The oscillator can also be quasi-optically iqjection-lock...

An effect, in planar GaAs MESFETs, whereby a sharp increaSe in optical gain at the transistor edges occurs, is reported. This gain effect only manifests when a large resistor is inserted in ser-ies with the gate, to produce the conditions for photovoltaic gate biasing. The mechanism for increased gãin, at t'he edges, is suggested to be due to carrier photogeneration in the substrate that is sub...

A new method for quasi-optically combining the output power of MESFET's is presented in which drain and source leads couple directly to the radiated field. The design consists of a planar grid of devices placed in a Fabry-Perot cavity. Capacitive feedback is provided to the gate. This is in contrast to previous MESFET grid designs where the radiated electric field was coupled to the drain and g...

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A 1.1-GHz fully integrated GaAs MESFET active inductor is presented in this paper. Both the inductance and loss resistance are tunable with the inductance independent of series loss tuning. The measured loss resistance is tunable over a 10to +15range with a corresponding change in inductance of less than 10% at 100 MHz and less than 4% for frequencies above 500 MHz. The inductance is tunable fr...

This paper describes the design, implementation and characterization of a high efficiency 10-GHz amplifier antenna array for spatial power combining. An average drain efficiency of 70% at 162 W EIRP, or about 1.5 W of transmitted power, is measured for an array of 16 amplifiers consisting of four 4-element subarays. The power combining efficiency of the 16-element array is above 79%. The active...

In this paper, we will discuss the modeling and simulation result of GaN MESFET device with our conventional computer added device simulator MEDICI. We will find out material parameter of GaN so that the device characteristics of simulation fit to experimentally built-on device characteristics. Then we will vary some important device parameters such as gate length, channel doping rate, and acti...