RF adapters may indeed cause changes in VSWR (Voltage Standing Wave Ratio). VSWR refers to the ratio of the amplitude of the standing wave belly voltage to the node voltage, and is an important indicator for measuring the impedance matching degree in RF systems. When the standing wave ratio is equal to 1, it indicates that the impedance of the feeder and antenna is completely matched, and all high-frequency energy is radiated out by the antenna without energy reflection loss.
One reason for the change in VSWR caused by RF adapters is that when the adapter is added to the RF path, if its impedance transformation improves the overall impedance matching of the system, the VSWR will correspondingly decrease. On the other hand, the addition of RF adapters may alter the phase of signals during transmission, which may improve the echo situation in the system and reduce VSWR.
However, it is worth noting that not all RF adapters will lead to an improvement in standing wave ratio. If the design of the adapter is improper or poorly matched with other components, it may actually lead to an increase in standing wave ratio. Therefore, when selecting and using RF adapters, careful evaluation and testing should be conducted based on specific application scenarios and system requirements.