Abstract
Generalized synthesis of the rat race ring coupler is developed with its four arms being allowed to have different characteristic impedances. The transmission line theory incorporated with the even-odd analysis is used to formulate the conditions for solving the circuit parameters. The solution shows that a rat race ring with a normalized area of 41.82% or 0.97λ-circumference can be achieved. Based on the solutions, simulated bandwidths of the new ring hybrids are reported. Two experimental circuits are measured for validation check. One uses stepped-impedance sections to realize the four arms for further size reduction. This circuit occupies only 13.12% of that of a conventional hybrid ring at 1GHz. It is believed that this implementation has the best size reduction for a microstrip ring hybrid in open literature. Measured scattering parameters show good agreement with the simulated results.
Original language | English |
---|---|
Pages (from-to) | 51-64 |
Number of pages | 14 |
Journal | Progress in Electromagnetics Research |
Volume | 108 |
DOIs | |
State | Published - 2010 |