in fig6 wherein eight devices labeled as a to h covering the four major factors with different permutations have been tested by comparing the device a and b the device with a collector emitter breakdown voltage bv ceo of 20 v shows improved vswr performance as compared with the device with bv ceo 15 v from results of devices a d and e we found that the ruggedness performance was improved with an ultimate vswr increasing from 3 1 6 1 to 8 1 as the resistor value the eebr was increased the base ballasting resistor r b also plays a role in optimizing the power transistor ruggedness performance the influence of r b can be inferred from the comparison between the device c and f increasing the r b from 125 u03c9 to 175 u03c9 in effect improves the vswr performance from 6 1 to 10 1 we also found that the use of clamping diode is also decisive to the device ruggedness for the device g which contains 20 v bv ceo 200 nm ere layer and 175 u03c9 r b the device is able to pass 8 1 vswr but still failed at 10 1 vswr however by adding clamping diodes at the output to clamp the voltage at 13 v the device h passes 15 1 vswr at v ce 3 6 v to 5 v under both room temperature and 90 u00b0 c base plate temperature the result has been verified for at least three times to show that indeed the h device is.