电压驻波比(VSWR)是指在传输线中的反射信号和前向信号之间的比率。它通常用于衡量无线电频段中无线电频率能量传输的质量。VSWR可以通过以下公式计算:VSWR = (Vmax + Vmin) / (Vmax - Vmin)其中,Vmax是最大的电压值,Vmin是最小的电压值。当VSWR等于1时,表示传输线完全匹配,反射信号等于零,前向信号等于传输线上的所有能量。当VSWR增大时,表示反射信号的能量增加,前向信号的能量减小,导致传输线中的损耗增加。
VSWR (Voltage Standing Wave Ratio, sometimes referred to as the vertical standing wave ratio) is a measure of the effective transmission power of a wireless signal through a power source, a transmission line, and ultimately into a load (eg, a power amplifier output through a transmission line, ultimately to an antenna). For an ideal system, the transmission energy is 100%, which requires an exact match between the source impedance, the characteristic impedance of the transmission line and other connectors, and the load impedance. Since there is no interference in the ideal transmission process, the AC voltage of the signal remains the same at both ends. In practical systems, impedance mismatch will cause some of the power to be reflected toward the source (like an echo). Reflection causes destructive interference, and voltage peaks and troughs are generated at different times and distances along the transmission line.
VSWR is used to measure the change in voltage and is the ratio of the highest voltage to the lowest voltage on the transmission line. Since the voltage in the ideal system remains the same, the corresponding VSWR is 1:1. When reflection occurs, the voltage changes and the VSWR increases -- for example: 1.2:1 or 2:1.