DAI Ke1,2, ZHANG Yan-jun1, WANG Wen-ming1,2, ZHANG Wei-qun1

(1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China;

2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China)

Abstract:To design the dimensions of sapphire loaded cavity for active H maser, we solved the transcendental equation which was deduced from Maxwell equations for the cavity in TE011 mode. By FEM (finite element methods) simulation of the cavity, the solution we got was confirmed. Then the ability of the cavity to sustain self-oscillation was calculated. With the active H maser SOHM-4 as a experimental bed, an H maser signalwith oscillation power of -102.93dBm was obtained from the sapphire loaded cavity, while the ion pump flux was about 1.1 mA. The signal power is almost as same as that of the standard active H maser, for the same ion pump flux.

Key words: H-maser; Sapphire loaded cavity; FEM (finite element methods) simulation