小巧但敦实：由100毫米铜管制成的磁环天线
Small but Tubby: A Magnetic Loop Antenna Made from 100 mm Copper Tubing
- ETH Zurich（苏黎世联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
介绍由100毫米铜管制成的小型发射磁环天线，通过设计减少电阻损耗，利用伺服电机自动调节频率等，控制布线有创新，室内损耗源于环境耦合，测量表明天线性能良好，专为室内操作开发。
AI中文摘要：
本文介绍了一种由直径达100毫米的铜管制成的小型发射磁环天线的电气模型、关键方程和实际构造。大导体表面积以及与真空电容器的大面积过渡旨在将电阻损耗降至最低。1.8兆赫兹至31兆赫兹的频率范围异常宽广。频率、阻抗匹配和方位角均由伺服电机自动调节。一个新颖之处在于控制布线在环形导体内的铺设方式，使得电机无需与环形导体进行电气绝缘即可安装。室内损耗主要源于与环境的近场耦合而非天线本身。温度上升测量证实大部分耗散功率被环境吸收而非天线组件。传导H场测量表明实测H场与根据天线几何形状和估计的环路电流计算出的理论自由空间H场之间具有良好一致性。环路电流根据实测天线带宽和施加的发射功率估算得出。该天线专为无法进行室外安装的室内操作而开发。
英文摘要：
This paper presents the electrical model, key equations, and practical construction of a small transmitting magnetic loop antenna built from unusually large 100 mm diameter copper tubing. The large conductor surface area and wide-area transitions to the vacuum capacitors were designed to minimize resistive losses. The frequency range from 1.8 MHz to 31 MHz is unusually wide. Frequency, impedance matching, and azimuth are all adjusted automatically by servo motors. Indoor losses originate predominantly from near-field coupling to the environment rather than from the antenna itself. Temperature-rise measurements confirm that the bulk of the dissipated power is absorbed by the environment, not by the antenna components. The conducted H-field measurements demonstrate good agreement between the measured H-field and the theoretical free-space H-field calculated from the antenna geometry and an estimated loop current. The loop current was estimated from the measured antenna bandwidth and the applied transmit power. The antenna was developed for indoor operation where outdoor installation is not possible.
