Modified Coaxial Cable Makes Components and Test Circuits

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  • Author: Scott Wartenberg
In the lab, coaxial cable is most often used to connect RF components. Yet, it is sur-prising that many engi-neers don’t realize that the coaxial cable itself can be built into an RF component. Physically modifying a coaxial cable can alter its RF behavior in a constructive way (see Figure 1). Understanding how these modifications change the RF behavior can enable new, prac-tical lab applications without the cost or the wait for commercial components. This paper examines the effect of modifying a simple RFcoaxial cable. Experimental measurements are made on a modified coaxial cable whose center conductor is offset (i.e., made eccentric) and which has a slot cut in the shield. Describing these modifications in terms of an equivalent circuit clarifies the RF changes and opens up new applications.