| Millimeter-wave communication systems often need to provide high power output,while the output capacity of the existing millimeter-wave power amplifier chip is verylimited, which requires to combine several power amplifier chips’ power so as toprovide high power output. Therefore, the power combining technology is the key to thedevelopment of high-power millimeter-wave power amplifier.After understanding the development of power combining technology at home andabroad, we introduced the basic theory of this technology, and analyzed the affectingfactors of the power combining efficiency. Two structures of waveguide-to-microstriptransition have been simulated and fabricated so as to verify their loss characteristics, bycomparison, we found that there were only structural differences existing in these twotransitions, we could make our choice by the specific circuit layout needs. In addition,four structures of power divider/combiner have been designed and simulated, bycontrast of their amplitude imbalance, operating bandwidth, isolation and size, theimproved T-junction has been chosen as a power dividing/combining network, and thefinal program which combines the probe transition and the improved T-junction to makea two-way power combiner has been established.A two-way passive power combining network has been fabricated and testedwhose measured performance seems good, the measured insertion loss is maintained at0.35dB-0.49dB with the band fluctuations less than0.14dB; the return loss is almostgreater than20dB. After adding the power amplifier chip to the amplifier module ofpassive network, the two-way power combining amplifier has been made out, themeasured performance parameters shows: during the operating band of30.2GHz-30.7GHz, the saturated output power is from28.97dBm to29.25dBm, the band gain isrelatively flat and the output power is close to1W; the combining efficiency is around at81%, which achieve the maximum efficiency of84.1%at30.25GHz, generally meet thedesign requirements. |
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