Introduction to CPCTL

Figure 8. Coplanar Waveguide

Figure 9. Coplanar Waveguide with Ground

Coplanar waveguide (CPW) uses a ground conductor that is coplanar with the signal conductor. Therefore, the impedance is controlLED by the signal line width and the ground gap. What this means is that you can keep the impedance constant as you taper the signal conductor's width down to meet a pin. This is perfect for matching to a component pin width without changing the substrate thickness!

The coplanar waveguide configurations that are most likely to be useful are: coplanar waveguide and coplanar waveguide with ground. Coplanar waveguide concentrates the field in the gap so it will have the best ability to taper in to a pin. However, it may require special attention if you are transitioning from microstrip line into CPW. In this situation, coplanar waveguide with ground (CPWG) may be easier to deal with since you can start with a wide gap (microstripline) and gradually transition to the coplanar waveguide with ground configuration.

Conclusion
You do not have to limit your designs to microstrip lines and striplines. Transmission lines, such as coaxial line, shielded microstrip line, and the coplanar waveguide family, can help designers solve real world layout problEMS while maintaining tight control of the waveguide characteristic impedance and physical dimensions.

[1] Transmission Line Design Handbook, by Brian C. Wadell, ISBN 0-89006-436-9, published by Artech House.

上一页  [1] [2] 

本文关键字：暂无联系方式制版技术，电子制作 - 制版技术