Research On SIW Power Combining Amplifier

With the rapid development of microwave and millimeter wave communication system,the requirement of efficient high power amplifiers is increasing. However, the output power attainable from a single solid-state device is basically limited by thermal and impedance matching problems. To meet system requirements it is therefore mandatory to combine several devices, thus attaining higher power levels.The key features of power splitting/combining devices are clearly their insertion loss, bandwidth and size. The techniques adopted for the optimization of device performance are strictly related to the type of splitting/combining structure and to the selected realization technology. Based on the study of SIW and waveguide power divider/combiner, the paper presents a four way SIW power divider/combiner and a three way waveguide power divider/combiner network. In addition, on the basis of six-port branch-waveguide directional couplers, a three way power divider/combiner has been designed and fabricated. Compared with other power dividers, the six-port waveguide power divider is a good candidate with high isolation and all ports matching. A three way power combining amplifier which combine the output power of three XD1001 driver amplifiers have been fabricated. In order to improve combining amplifier upgrading and maintenance, we integrate the power MMIC in a module through the waveguide to microstrip transition. And the module connects the power distribution network by the means of standard rectangular waveguide, which is beneficial to the installation and replacement. Compared with the power divider/combiner that integrated MMIC, the modular design makes the chip more dispersed and each MMIC has a heat carrier, which heat dissipation is better.By using low-loss waveguide combining and solid-state amplifier modules, the output loss is minimized, the proposed three-way combining power amplifier have a bandwidth from 33 to 35 GHz with 21.53 d Bm saturation power output. The measured solid-state amplifer modules saturation power output is higher than 19.14 d Bm. The average overall power-combing efficiency is 86.33%, and the maximum power-combing efficiency is 95.35%.