Equivalent Circuits and Analysis of a Generalized Antenna System [Antenna Applications Corner]
Equivalent Circuits and Analysis of a Generalized Antenna System [Antenna Applications Corner]
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DOI：
10.1109/map.2021.3053976
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发表时间：
2021-04
影响因子：
3.5
通讯作者：
Yi Huang;Ahmed Alieldin;Chaoyun Song
中科院分区：
文献类型：
--
作者：
Yi Huang;Ahmed Alieldin;Chaoyun Song
众所周知，当负载的阻抗是源阻抗的复共轭时，电气或电子系统中的最大功率可以传递给负载，尽管功率传输效率仅为50%。这一事实是否也适用于无线电系统？这个问题已经存在了几十年。本文重新研究了天线系统的等效电路。本文证明了基于thsamuvenin和Norton定理的经典等效电路模型不适用于接收天线系统，因为天线不能简单地由电压或电流源近似。需要一个恒定的电源，但不是现成的。因此，介绍了两种新的通用电源模型，并对其进行了检验。研究发现，当考虑天线损耗时，它们可能适用于发射天线系统，但对于接收天线系统则不够精确。因此，提出了一种新的特殊的恒功率源模型，并证明了该模型可以准确地模拟接收天线的行为。当负载阻抗为天线阻抗的复共轭时，获得最大功率，同时使功率传输效率最大化（天线系统无损时可达100%）。
It is well known that the maximum amount of power in an electrical or electronic system can be transferred to a load when its impedance is the complex conjugate of the source impedance, although, the power transfer efficiency is only 50%. Is this fact true for a radio system, as well? The question has existed for decades. In this article, the equivalent circuits of antenna systems are reexamined. It is demonstrated that classical equivalent circuit models based on the Thévenin and Norton theorems are not suitable for a receiving antenna system since the antenna cannot be simply approximated by a voltage or current source. A constant power source is required but not readily available. Thus, two new general power source models are introduced and examined. It is found that they may be suitable for a transmitting antenna system but not accurate enough for a receiving antenna when the antenna loss is taken into account. A novel special constant power source model is therefore proposed and shown to accurately simulate the behavior of a receiving antenna. When the load impedance is the complex conjugate of the antenna impedance, maximum power is obtained, and the power transfer efficiency is simultaneously maximized (up to 100% if the antenna system is lossless).