Understanding the VSWR of an antenna

The Voltage Standing Wave Ratio (VSWR) is a measure of the matching of the antenna to the feed line connecting to it. VSWR or Return Loss (RL) are two parameters both measure how well the component is matched to other system components. Both are used interchangeably, there is a bandwidth range that antennas must satisfy and is defined in terms of VSWR.

The range of values for VSWR is from 1 to ∞. Generally speaking , A VSWR value under 2 the antenna matched to the transmission line is considered very good. Furthermore, a low VSWR will minimize reflections from the antenna.

The higher the VSWR is , the more power is reflected from the antenna and therefore not transmitted , furthermoe, more power is reflected to the radio, which is transmitting. But note tha VSWR is an indication of how much power is delivered to an antenna. This doesn’t mean the antenna radiates all the power it receives.So, a low VSWR is considered the antenna is well matched, but but doesn’ mean the power delivered is also radiated.

Hence matching of the antenna to the radio or transmission line is definitely critical to not only the performance of the individual device, but also the entire network.