双RF软件简化功率放大器设计设计流程双RF软件简化功率放大器设计设计流程 By Ivan Boshnakov, Senior Principal Design Engineer and Jon Divall, Engineering Manager, Aerial Facilities Ltd, Chesham, UK Planet Analog A new amplifier had to be developed to replace an existing amplifier which had been a sound product for many years, but the RF bipolar power transistors used in it had become obsolete. This pre-existing amplifier works in Class A mode and delivers P1dB in excess of 20W in a 20MHz bandwidth. Its center frequency is tunable from 380 to 470 MHz. It is in a 2 stage single ended configuration with gain of more than 23.0 dB and the input/output return loss of better than 20dB. This amplifier has been designed by "cut and try" modification of the schematics and topologies suggested by the manufactures of the transistors. The topology is mixed……