Microwave Transmitting System Based on Four-Way Master–Slave Injection-Locked Magnetrons and Horn Arrays With Suppressed Sidelobes

This paper proposes an S-band microwave transmitting system based on four-way master-slave injection-locked magnetrons, which has the advantages of low cost and high efficiency. The transmitting system consists of a microwave generator and an antenna array. The microwave generator provides four-way excitations with equal phases and amplitudes to the antenna array, where a radial divider is applied to produce and control the four-way injected signals to lock the slave magnetrons. The antenna array includes four pyramid horns and two layers of artificial materials with 2-D periodic corner-truncated square slots, which are arranged to enhance the gain and suppress sidelobes. The transmitting system is fabricated and measured. Experimental results show that the microwave generator is able to produce four-way excitations with the phase differences less than 12° and the amplitude errors less than 3%. The antenna array provides a gain of 27.2 dB, sidelobe levels less than -10 dB, and reflection coefficients less than -15 dB. The whole system operates stably at 2.46 GHz with a transmitting power of 3.5 kW.