A wideband twenty-element microwave spatial power combiner

In this paper, a wideband coaxial power combiner with tray configuration, employing twenty 1-Watt elements mounted on antipodal finline boards, is implemented to achieve a rather high power microwave amplifier in the frequency band of 6-18 GHz. The average gain, Continuous Wave (CW) output power and Power-Added Efficiency (PAE) of the combiner are measured as 17 dB, 15 Watts and 17%, respectively with ripples of less than 3 dB. In order to investigate the combining efficiency, the passive structure is fabricated and tested in the first step. Its main components, i.e. the coaxial adapter and the antipodal finline boards, are synthesized by using Klopfenstein s optimum impedance taper, and simulated by Ansoft HFSS. Next, the active devices are added to the system. Stability, thermal management and life time issues are examined and addressed in this step. The system reliability is also demonstrated as graceful degradation due to the failure of devices.