Research On W-Band Power Combining Technology

W-band communication radars often require output power reaching watt level, however, the available output power providing from monolithic power amplifiers of Wband is only milliwatt-level. As the result, the power combining technology must be employed to achieve higher power. Nevertheless, the loss of signal at W-band is inevitable and high, moreover, the shorter wavelength urges harsher size of circuit processing. The structure of power combining, using at lower frequencies, usually do not work well at Wband due to the limit of size. In this thesis, the waveguide structure with lower insertion loss is used in the research of power combiner at w-band and the concise combining network is employed to meet the processing requirements. The content is as follow:1. The transition method between w-band waveguide and microstrip is studied, and the feasibility of the structure that the microstrip probe and the fin line transition in wband power combining technology is verified. The double microstrip probe structure based on TE20 mode is developed on the basis of traditional waveguide-double microstrip probe structure, solving the problem that the isolation between the double microstrip probes can only reach-6dB.2. The back to back network structure uniting the 1800 hybrid bridge with the fin line transition is adopted, whose test results indicate that the insertion loss of the whole passive network is 2.5dB ? 0.5dB at the frequency range of 85~98GHz.3. The novel TE10-TE20 mode transition structure is presented, which is combined with TE20 double microstrip probe structure as the power split/combine network.4.W-band planar magic T is researched and designed, whose test results suggest that the insertion loss is 3.4dB at the frequency band of 85~105GHz. The passive split/combine network combining single probe with the planar magic T is designed, whose test results indicate that its insertion loss is 2.7dB.5. The power of the monolithic power amplifiers at W-band is tested. The combining structure uniting with planar magic T and E-plane microstrip probe is selected to realize 2-way power combining after comparing some kinds of power split/combine network. The final test results show the saturation output power of the combiner is greater than 10 dBm and the efficiency is higher than 80% at the frequency band of 75~100GHz.