Effects of the operating conditions on the performance of IMPATT amplifiers

The purpose of this paper is to shed further light on the effects of the operating conditions, such as the operating frequency and the DC-bias current, on the performance of IMPATT amplifiers. It is shown that the characteristics of the IMPATT amplifier depend strongly on the characteristics of the IMPATT diode. It is found that increasing the frequency reduces the bunching and acceleration, and the premature collection of the avalanche-generated pulse. This is attributed to the decrease of the space charge effect and the depletion layer width modulation effect with increasing frequency. It is also concluded that by increasing the DC-bias current, the bunching and acceleration of the avalanche generated pulse increases, while the premature collection of the pulse decreases. This improves the IMPATT amplifier performance. Optimization of the amplifier gain and its dependence on the operating conditions are introduced and discussed