Basic knowledge and selection methods of microwave and millimeter wave coaxial connectors

作者： 沃锌科技 时间：2023-11-28 15:57:06 阅读：15

When it comes to microwave circuits, coaxial connectors cannot be omitted. No matter which frequency band your circuit is in, as long as it needs to be measured on instruments such as spectrographs and network analyzers, you need to use coaxial connectors. connector

Among all 18GHz connectors, APC-7 (Amphenol Precision Connector -7 mm) has the lowest reflection coefficient and can provide the best repeatability measurement. This connector was jointly developed by HP and Amphenol in the 1960s. This is a connector designed with no polarity, suitable for applications with the most stringent requirements, especially for metering and calibration applications.

N-connector

I believe this is the connector that most people come into contact with in their daily lives. As long as you are working on circuits, you will probably have used it before (unless you are working on millimeter wave circuits, you may not have used it). The SMA (Micro A) connector designed by Bendix Scintilla is one of the most commonly used connectors for RF/microwave applications. It uses semi-rigid cables and is suitable for infrequent connections. Due to the difficulty of fixing the dielectric support, the reflection coefficient of most SMA connectors is higher than other connectors when used at 24 GHz.

3.5mm feedthrough

One end of the feedthrough adapter is a 1.0mm female connector, and the other end is a glass to metal sealed interface. It is suitable for ultra-high frequency (up to 110 GHz) signal hopping from coaxial to microstrip line packaging or circuit boards.

2.92 mm connector

The 2.4 mm connector is a connector jointly developed by HP, Amphenol, and M/A-COM for 50 GHz. This design solves the vulnerability issue of SMA and 2.92mm connectors by increasing the outer wall thickness and strengthening the slots. It can accurately adapt to SMA, 3.5mm, and 2.92mm connectors. However, due to the fact that there are not as many manufacturers producing 2.4mm connectors as K-type connectors and their prices are higher, their applications are not as widespread as K-type connectors.

1.85mm connector

The 1.0 mm connector is designed to support all transmission modes up to 110 GHz, which is an important achievement in the precision manufacturing industry that enables reliable and flexible interconnection.

To summarize, if the circuit you need to measure and test is below 18GHz, you can choose SMA connectors, N-type connectors, and APC-7 connectors. The specific choice depends on your circuit type, cost, etc. If your boss has too much money to spend, you can also use K-type connectors and other original works on microwave and millimeter wave coaxial connectors. If you are measuring and testing in the millimeter wave frequency band, you can choose a K-type connector or a 2.4mm connector. Why not choose a 3.5mm connector? Because compared to K-type connectors, it has neither price advantage nor performance advantage (applicable frequency is not as high as K-type connectors).