A Ka-band Amplifier System with Large Gain and Wider Bandwidth for Onboard Telemetry Transmission

Here, we present the design and development of a Ka-band amplifier system using cascaded topology. The Gallium Arsenide (GaAs) pseudomorphic High Electron Mobility Transistor (pHEMT) based amplifier system is designed to produce a reasonably high gain over a wide bandwidth with high output power at Ka-band. The Q-point of the amplifier system has been set through bias to confine its operation between the active and saturation region of the solid-state power amplifier (SSPA). It helps in realizing the maximum output power with marginal compromise in the linearity by ensuring system operation does not exceed the P1 dB compression point. The realized prototype has been experimentally evaluated through a series of measurements. It demonstrates a realized gain of 32dB with an operational bandwidth of about 17% (27 GHz to 32 GHz). The achieved output power is 1 Watt (
$+\ \mathbf{30}$
dBm) with a gain flatness of better than
$\pm \mathbf{0.5}\ \mathbf{dB}$
.