Steps Approximate Analysis and Design Charts of Raised Cosine Impedance Tapered Microstrip Lines by Waveguide Model

摘要

In the previous paper(1), the linear and the raised cosine tapered microstrip lines were analyzed by the waveguide model. The taper part was approximating like stairs and scattering coefficients of each step were combined by using a generalizing scattering method (2). The best shape of the taper was examined by using the characteristic chart. Moreover, it was shown that the calculation data by this analytical method are suitable for the experimental data well for the linear tapers in Ref. (3). In this paper, the reflection coefficients of the taper whose characteristic impedance changes by the taper whse characteristic impedance changes by raised cosine function are analyzed (4). The actural width of the line is obtained from the characteristic impedance. Then, the taper is analyzed by approximating inthe stairs and using the waveguide model as Ref (1). The charcteristic chart that shows the return loss is made to obtain the best shape that the reflection coefficient in the utilization band becomes small(1),(4). In addition, another characteristic charts are defined to find the n and the taper length L that the reflection coefficients at the specific frequency become minimum.