0191-9067/85 $3.00 + .00 Copyright ® 1985 SUNSAT Energy Council FUNDAMENTAL STUDY ON SPS RECTENNA PRINTED ON A SHEET OF COPPER CLAD LAMINATE KIYOHIKO ITOH, YASUHIRO AKIBA, TAKEO OHGANE and YASUTAKA OGAWA Department of Electronic Engineering Hokkaido University Sapporo 060 Japan Abstract — This paper proposes the use of a microstrip antenna as a competitor to the linear antenna for "Rectenna” in SPS (Solar Power Satellite) project. The microstrip antenna features high-Q and higher resonance-harmonics which are not integer multiples of the dominant resonance frequency if a circular microstrip antenna (CMSA) is chosen. This paper experimentally clarifies wide frequency band characteristics of the CMSA. It is especially shown that the CMSA with slits possesses an excellent higher harmonic suppression characteristic. The CMSA with slits is used as a receiving antenna, a higher harmonic rejection filter as an input filter, a diode bridge using four Toshiba 1SS154 Si Schottky diodes as a rectifier, a by-pass chip condenser as an output filter in the rectenna. The rectenna was built as a trial and its RF-DC conversion efficiency was measured. In the experimental results, the conversion efficiency is not high. However, the rectenna obtained in this paper has many unique and attractive properties — low in profile, light in weight, compact and conformable in structure, easy to fabricate, and easy adaptation to the photoetching technique in fabrication. INTRODUCTION The “Rectenna” receives microwave power (2.45 GHz) from SPS (Solar Power Satellite) and is an important basic element in the Earth Station Terminal in the SPS project. It has no previous counterparts in electric power engineering or microwave and antenna engineering. The name of the rectenna comes from a receivingrectifying antenna. The rectenna itself consists of a receiving antenna, low-pass filter and rectifying diode. The low-pass filter is used mainly for suppression of reradiation of higher harmonic microwaves, which are generated by the rectifying diode. The SPS baseline rectenna has been developed by Raytheon Company, where they have used a dipole antenna with ground plane as the receiving antenna (1). Gutmann et al. have investigated the possibility of using a printed circuit dipole with ground plane, and a printed circuit Yagi-Uda with or without ground plane, as the receiving antenna. All of the above mentioned antennas are known as linear antennas in antenna engineering (2). The linear antenna is generally featured by low-Q and higher resonance-harmonics of integer multiples of its dominant resonance frequency (2.45 GHz). These features are undesirable for suppression of higher harmonic re radiation. This paper proposes the use of a microstrip antenna as a competitor to the linear antenna for “Rectenna” in the SPS project. The microstrip antenna is featured by high-Q and higher resonance-harmonics which are not integer multiples of the domi-
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