A Power Bipolar Transistor Optimized for Linear Performance up to 5 GHz

A linear power transistor with 1.6 μm emitter width, 34 emitter sites, and individual emitter ballast resistors has been developed using a new transistor process which has excellent reproducibility. Such a transistor has been packaged with a single stage of input matching which transforms the input impedance to an easily usable value in the 4 GHz region. Experimental linear output power of 500 mW has been measured with a corresponding gain of 7.5 dB at the 1 dB gain compression point at 4 GHz, and with useful gain and power at 5 GHz. Data is presented on the transistor's linear power performance, S-parameters from 2 to 5 GHz, and third-order intercept points.