Ka-band Radial Waveguide Power Combiner

Two main parts are proposed in this paper. After investigating a lot of papers about power combining technique, we designed and assembled a Ka-band spatial-waveguide power amplifier in the first part. The design of Low Noise Amplifier (LNA) including how to test the electric parameters is introduced in the second part .The main contents are the follows:1. By analyzing and comparing the characteristics of various power combing techniques, we chose a spatial power dividing/combining structure as the scheme of the power amplifier.2. Analyzed the principle of the spatial-waveguide dividing/combining structure. A four-way waveguide power dividing/combing circuit has been designed, After modeling and optimizing by the software CST Microwave Studio, we made a practical back-to-back structure In the frequency range of 34 to 36GHz, the return loss is less than 15 dB, and the insert loss is better than 2dB3. Designed and assembled the Ka-band power amplifier. In the frequency range 34 to 36 GHz; its highest saturation output power is up to 0.36 watts (25.5 dBm). We can estimate the highest power combining efficiency is up to 85%.4. In the last chapter a microwave low-noise amplifier is proposed in this paper. The characteristic of the LNA designed and manufactured is: frequency range: 22-27.5GHz, gain: G= 56.7dB, gain flatness: G<±2 dB, noise figure: Nf<3.5dB.