Experimental comparison of two ultra-broad microwave combiner/divider

Reports the results achieved to date from combining two 2-18 GHz MMIC medium power amplifiers with ultra-broad band planar combiners. The design goal is to realise a 2-18 GHz 1 watt power amplifier. In the design of ultra-broad band high power amplifiers, it is necessary to combine the output powers from several high power discrete or monolithic devices. The devices chosen were Texas Instruments MMIC amplifier chips, TGA 8300 and TGA 8220. These distributed MMIC amplifiers exhibit good input and output match, better than 2.0:1 VSWR, with typically 6 dB gain and up to 0.4 W in output power. A seven-section Wilkinson (1960) combiner/divider was designed, fabricated and shown to exhibit very good performance compared to a nonuniform tandem quadrature coupler designed and constructed by Uysal and Aghvami (see IEEE Trans., MTT-37, no.6, 1989)