MAXIMUM POWER OF THE HF ANTENNA TUNER SWITCHED BY PIN DIODES AT LOAD MISMATCH

Abstract

PIN diodes, as inertial nonlinear elements, are widely used in transceiver equipment of various frequency ranges as limiters, attenuators and phase shifters. Also, with their help, it is possible to implement double-sided switching elements used, among other things, in switches and automatic antenna-matching devices of the HF range. Literary sources note that PIN diode switches in the HF range are capable of switching power up to 2 kW. In this case, only the task of switching the sub-octave bandpass filters of the transmitter is meant when operating at a perfectly matched load in a 50 Ohm path. The article discusses the features of the operation of PIN diodes in the HF range and determines the limiting values of the switched power depending on the parameters of the device and the load resistance. Examples of the circuit design of high-speed control circuits are given. The analysis of the maximum power of an automatic antenna-matching device of the HF range, carried out using the example of the most famous samples, with a load mismatch with PIN diodes, showed that in the case of a matched load, they can be used up to power levels practically equal to 2 kW. With a strong load mismatch, which is observed in most practical cases, especially when using communication facilities on mobile objects with electrically short antennas, the maximum power levels are reduced to 170 W when operating at frequencies above 3 MHz and to 100 W when operating at frequencies above 1 MHz.