Discussion on Power Capacity of RF Coaxial Connectors(2)

Working Frequency

The power tolerance of the RF coaxial connector will decrease as the signal frequency increases. The change of the transmission signal frequency directly leads to the change of the loss and the voltage standing wave ratio, which affects the transmission power capacity and the skin effect. For example, a general SMA connector can withstand about 500W of power at 2GHz, and can withstand less than 100W of average power at 18GHz. For passive components such as attenuators and loads with frequencies higher than 18GHz, the average power withstand is mostly within 100W. For the millimeter-wave frequency band, the average power of a 1.85mm 67GHz fixed attenuator is within 10W, and the average power of a 1.85mm 67GHz load is within 22W. The 2.92mm attenuator and load can be selected more, and the average power can withstand up to 100W.

VSWR

The RF connector is designed with a certain electrical length. In a line of limited length, when the characteristic impedance and the load impedance are not equal, a part of the voltage and current from the load end is reflected and returned to the power supply side,such as SMA Connector.

The wave is called Reflected waves; the voltage and current from the source to the load are called incident waves. The composite wave of the incident wave and the reflected wave is called a standing wave. The ratio of the maximum voltage to the minimum value of the standing wave is called the voltage standing wave ratio (also known as the standing wave coefficient). The reflected wave occupies the channel capacity space, resulting in a reduction in the transmission power capacity.

Insertion Loss Insertion Loss (IL) refers to the loss of power on the line due to the introduction of RF connectors. Defined as the ratio of output power to input power. There are many factors that increase the insertion loss of the SMA connector, mainly including: mismatch of characteristic impedance, assembly accuracy error, mating end face clearance, axis inclination, lateral offset, eccentricity, machining accuracy and electroplating. The difference between the input and output power due to the presence of losses also affects the withstand power.

Altitude Pressure

The change of air pressure leads to the change of the dielectric constant of the air section, and the air is easily ionized to produce corona at low pressure. The higher the altitude, the lower the air pressure and the less power capacity. [SMA Connector]

Related Articles:

1.Discussion on Power Capacity of RF Coaxial Connectors(1)

2.Discussion on Power Capacity of RF Coaxial Connectors(3)