Isosceles-Trapezoidal-Distribution Edge Tapered Array Antenna with Unequal Element Spacing for Solar Power Satellite
Isosceles-Trapezoidal-Distribution Edge Tapered Array Antenna with Unequal Element Spacing for Solar Power Satellite
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DOI：
10.1093/ietcom/e91-b.2.527
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发表时间：
2008-02
期刊：
影响因子：
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通讯作者：
A. Baki;K. Hashimoto;N. Shinohara;T. Mitani;H. Matsumoto
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文献类型：
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作者：
A. Baki;K. Hashimoto;N. Shinohara;T. Mitani;H. Matsumoto
到2050年，地球将需要相当于目前商业发电量3到5倍的可持续电力来源。太阳能卫星（SPS）是满足未来巨大能源需求的一种选择。SPS可以向地球以微波（MW）的形式发送大量的能量。SPS需要一种高效的微波功率传输系统。SPS的一个关键目标是保持最高的波束效率（BE），因为来自SPS的微波将转换为公用电力，而不像来自通信卫星的毫瓦。SPS的另一个关键目标是保持旁瓣电平（SLL）尽可能小，以减少对其他通信系统的干扰。降低SLL和增加BE的一种方法是使相控阵天线的边缘逐渐变细。然而，减少激励需要一个技术上复杂的系统。另一种实现最小SLL的方法是随机间隔单元位置，但它不能保证较高的BE，并且随机单元位置的确定也是一项困难的任务。采用等腰梯形分布（ITD）边锥天线，研究了全边锥和均匀振幅分布之间的优化问题。在过渡段边缘逐渐变细的情况下，可以实现最高的波束收集效率（BCE）和最低的SLL（除了最大SLL），过渡段边缘逐渐变细的天线在技术上更好。采用不等间距的天线单元，从最大旁瓣电平（MSLL）和BE两方面进一步提高了过渡段的性能。采用不等单元间距（ITDU）的过渡段边缘逐渐变细可以显著降低MSLL。在ITDU中BE也是最高的。ITDU不等元位置的确定是很容易的。ITDU是第一次试验的新概念。讨论了ITDU相对于ITD和高斯边锥的优点。
SUMMARY The Earth will require sustainable electricity sources equivalent to 3 to 5 times the commercial power presently produced by 2050. Solar Power Satellite (SPS) is one option for meeting the huge future energy demand. SPS can send enormous amounts of power to the Earth as the form of microwave (MW). A highly efficient microwave power transmission (MPT) system is needed for SPS. A critical goal of SPS is to maintain highest Beam Efficiency (BE) because the microwaves from SPS will be converted to utility power unlike the MW from communication satellites. Another critical goal of SPS is to maintain Side Lobe Levels (SLL) as small as possible to reduce interference to other communication systems. One way to decrease SLL and increase BE is the edge tapering of a phased array antenna. However, tapering the excitation requires a technically complicated system. Another way of achieving minimum SLL is with randomly spaced element position but it does not guarantee higher BE and the determination of random element position is also a difficult task. Isosceles Trapezoidal Distribution (ITD) edge tapered antenna was studied for SPS as an optimization between full edge tapering and uniform amplitude distribution. The highest Beam Collection Efficiency (BCE) and lowest SLL (except maximum SLL) are possible to achieve in ITD edge tapering and ITD edge tapered antenna is technically better. The performance of ITD is further improved from the perspective of both Maximum Side Lobe Level (MSLL) and BE by using unequal spacing of the antenna elements. A remarkable reduction in MSLL is achieved with ITD edge tapering with Unequal element spacing (ITDU). BE was also highest in ITDU. Determination of unequal element position for ITDU is very easy. ITDU is a newer concept that is experimented for the first time. The merits of ITDU over ITD and Gaussian edge tapering are discussed.