X And Ka Band Power Combining Research

In order to enhancing the operating range and battlefield capability of modern radar and communication systems, it is permanently required to increase the output power of PAs in solid-state transmitters. One promising way to realize this is to adopt power-combining technology, of which the key point is developing wide-band power dividing/combining networks with low insertion loss.In this dissertation, several broadband low loss power dividing/combining structures operating on X and Ka frequency bands were introduced and verified respectively. The feasibility to implement high power and high efficiency combination employing such structures was evaluated.Firstly, an improved X-band E-plane waveguide-microstrip dual-probe structure was researched and a four-way power splitting/combining network was fabricated. Inherent matching of E-T was obtained through two height-reduced waveguides. Therefore, it could work on the entire waveguide bandwidth. The back-to-back passive network experiment results indicated an insertion loss lower than 0.9 dB, combining efficiency over 90% in the frequency range 8~11GHz. The combined SSPA was assembled with four 18-watts power modules operating on 8.5~10.5GHz, providing 30dB small signal gain and 48dBm maximal saturated output power.Moreover, in Ka-band, improved E-plane waveguide-microstrip dual-probe structure, waveguide coupler-microstrip dual-probe structure and E-T branch hybrid with a thin film resistor inserting in the junction were analyzed, simulated, manufactured and mesured respectively. Comparison and discussion were made to these networks in detail.Various compact configurations can be obtained through specific arrangements with the proposed schemes. Thus, this thesis is expected to offer some valuable choices for broadband high power combinations in micowave and millimeterwave applications.