Modification of the Rat Race Circuit

The Rat Race circuit is a four port made of a loop of a transmission line. Only One side of the four sides of the loop has transmission in opposite phase as compared with the other three sides. The phase difference of four right angles or the multiple has no practical significance. With this in mind，a variety of modifications to the basic form of the Rat Race circuits introduced. This technique brings out larger sizes for the Rat Race circuit as well as modifications of the terminating immittances and power distribution ratios. Further development is obtained by the diagonalization of the image immittance matrices of the Rat Race circuit. This technique shows the possibility of broadbanding of the performance of the Rat Race circuit