Millimeter Wave Power Synthesis Of Network Design

With the rapid development of millimeter-wave technology, solid state poweramplifiers have more extensive applications in microwave and millimeter-wavecommunication system. The output power of a single solid-state amplifier is limited,usually combining several devices to achieve high power level.At first, this paper discussed several factors which can affect the combiningefficiency. Then has researched waveguide spatial power combining technology, thetheory of waveguide T-junction, E-plane waveguide directional coupler, waveguide tomicrostrip transitions and waveguide magic T were analyzed in detail. Based on it,several3dB power combiners and two kinds of four-way power combiner weredesigned. Some of them were processed and tested.In the test results, in24GHz-33GHz, waveguide T-junction’s insertion loss is lessthan3.4dB. Because isolation between output ports of three-port power combiner arepoor, four-port power combiners were designed in this paper. In26GHz-31GHz, thedirectional coupler’s insertion loss is less than3.4dB and amplitude imbalance is lessthan0.4dB. It has a excellent isolation between output ports. This paper presentedwaveguide magic T which use vertebral body matching. Based on it, a novel design ofwaveguide magic T was proposed, which can effectively expand the bandwidth. Take-20dB as a benchmark, the bandwidth is increased by25%. Three kinds of waveguide tomicrostrip probe transition were designed, in the test results, the maximum insertionloss of three designs are1.5dB,1.4dB,1.7dB, and the insertion loss contains the loss ofabout20mm’s microstrip. The performance can meet the requirements of engineeringapplication.For the consideration of the miniaturization, SIW is used to design the Ka–bandT-junction, in the test results, in24GHz-33GHz, the insertion loss is between-4.4dB—-6.3dB, The performance can meet the requirements of engineering application.In addition, two kinds of four-way power combiner were proposed. Both the twodesigns are two level circuit cascade. The first design: first level of it is a3dBdirectional coupler, second level of it are two waveguide T-junctions. The calculated combining efficiency is up to97.3%. The second design: both of two levels are3dBdirectional couples, compared with the former it can get a good isolation between poweroutput ports. The calculated combining efficiency is up to97%. Both of them have alow insertion loss and high power capacity.