Analysis and Design of a Planar Rat-Race Coupler with Arbitrary Power Division Ratio and nth Harmonics Suppression

ABSTRACT

In this article, a planar, unequal rat-race hybrid with harmonic suppression is presented. It is constructed by replacing the quarter-wavelength transmission lines of unequal rat-race coupler with their equivalent T-shaped transmission lines. Compared with the conventional coupler, the proposed structure can achieve arbitrary power division ratios, deep harmonic suppression, and size reduction. For verification, a prototype operating at 1 GHz with third-order harmonic suppression is designed, simulated, and measured. The validity of this design has been proved by the consistency of the simulation and measurement results. Moreover, the performance variations with the different parameters are mainly simulated and analyzed.

KEYWORDS:

• Arbitrary power division
• harmonic suppression
• miniaturization
• rat race hybrid

Additional information

Funding

This work was supported in part by the program for Changjiang scholars and innovative research team in university (IRT1212) and the project of construction of innovative teams and teacher career development for universities and colleges under Beijing Municipality (IDHT20130518).