What is the return loss of SMA connector

Return loss and VSWR (Voltage Standing Wave Ratio) are measurements for the same parameters; they have a logarithmic transition; see this link for a comparison table of return loss and VSWR.

The return loss is an important parameter of an RF connector; as the value increases, the signal loss decreases, and the client receives improved signal transmission quality.

The return loss of SMA connectors is not fixed and will vary depending on numerous factors such as frequency, connector structure, and cable type.

Structure of connectors

Straight SMA connectors offer a lower return loss than right angle SMA connectors by around 5.5 dB.

The SMA connector that connects to the cable is superior to the PCB type.

Contact solder is preferable to crimping.

SMA Connector Male Crimping For RG174

Frequency

When the frequency is raised, the return loss decreases, which means the transmission line experiences more reflection loss. For example, at 3 GHz, the VSWR for the SMA connection plug crimping for RG174 is approximately 1.10 (return loss 26.44dB), at 6 GHz, the VSWR is around 1.12 (return loss 24.94dB), and so on.

SMA Jack 4 Hole Flange For PCB.

Type of Cable

Semi-rigid cable, such as RG405 has lower return loss than flexible cable, such as RG58 and RG174, since RG405 has higher shielding performance and must be soldered with inner and outer contacts, resulting in great signal quality.

SMA Plug Right Angle Soldering For RG405