Study of Ultra-High Efficiency Planar Antennas

The purpose of this study is to establish a design method of radial line slot antennas （RLSA）which are high gain and high efficiency planar arrays. It consists of searches for (a) slotarrangement for circularly- and linearly-polarized RLSA's，(b) efficiency optimization（>80%）和(c)低成本和mass—产品结构关键技术utilized here is the field analysis to estimate the lot coupling to aversized radial waveguide as良好的反映形式提供结构，Following results were obtained.1. the shape offeeding structure was numerically optimized and the overall antenna rection was suppressedbelow - 17db .2. In double - layered RLSA with uniform slots，the slot length and the spacings were optimized experimentally. the antenna efficiency of 75% at thegain of 36.3dBi was realized，which is twice as high as of conventional planar arrays.3. The coupling between slots and Theradial waveguide,was analyzed by moment method. It enables the aperture illumination control by varying the slotlength and the spacing. Reflection from slots可以改进和支持基于的upon thisanalysis.4. Single layered RLSA's of 25 to 60cm in diameter，3.关于80%的卓越效率是真实的，这些都是非常好的attractive in terms of cost and mass - producibility and are now used commercially.5. Slotlinearly - polarized RLSA was proposed and the efficiency of 48% was observed.Thebandwidth widening,reuse of the termination loss power and techniques for tilted beam and dual polarization are leftfor further study。

The purpose of this study is to establish a design method of radial line slot antennas (RLSA's), which are high gain and high efficiency planar arrays. It consists of researches for (a) slot arrangement for circularly- and linearly-polarized RLSA's, (b) efficiency optimization (>80%) and (c) low-cost and massーproducible structure. Key technology utilized here is the field analysis to estimate the slot coupling to aversized radial waveguide as well as the reflection form the feeding structure. Following results were obtained.1. The shape of the feeding structure was numerically optimized and the overall antenna reflection was suppressed below ー17dB.2. In doubleーlayered RLSA with uniform slots, the slot length and the spacings were optimized experimentally. The antenna efficiency of 75% at the gain of 36.3dBi was realized, which is twice as high as that of conventional planar arrays.3. The coupling between slots and the radial waveguide, was analyzed by moment method. It enables the aperture illumination control by varying the slot length and the spacing. Reflection from slots can also be evaluated and suppressed based upon this analysis.4. Singleーlayered RLSA's of 25 to 60cm in diameter, were designed based upon 3. The excellent efficiency of about 80% were realized. These are also very attractive in terms of cost and massーproducibility and are now used commercially.5. Slot arrangement for linearlyーpolarized RLSA was proposed and the efficiency of 48% was observed.The bandwidth widening, reuse of the termination loss power and techniques for tiltedーbeam and dualーpolarization are left for further study.