Dc biasing and ac loading of high gain frequency transistors

Abstract

A small sized energy conveying and signal dissipating loading apparatus for use in the testing of a transistor of the high gain high frequency type is disclosed. The energy conveying and loading device of the invention employs a transmission line-like network of distributed components in order to roll off and dampen or dissipate the high frequency alternating current response of the transistor under test while also being electrically invisible for measuring the low frequency or DC characteristics of the transistor under test. The described energy communicating and loading apparatus is compatible with the temperatures of a test environment for even the most extreme environment transistor devices and allows convenient placement in the test environment immediately adjacent the transistor under test. The load allows testing of multiple transistor devices with reasonable space and cost requirements. Use of the energy communicating and loading invention with a hetrojunction bipolar transistor of the microwave type and in conjunction with discrete bypass capacitors are also disclosed.