A Compact Rat-Race Coupler with Harmonic Suppression for GSM Applications: Design and Implementation Using Artificial...

Area of Science:

• Electrical Engineering
• Microwave Engineering
• Antenna Design

Background:

• Conventional rat-race couplers are large due to long branch lengths (λ/4 and 3λ/4).
• Existing designs often lack effective harmonic suppression, impacting device performance.

Purpose of the Study:

• To design and fabricate a compact microstrip rat-race coupler operating at 950 MHz.
• To significantly reduce the physical footprint of the rat-race coupler.
• To enhance harmonic suppression capabilities.

Main Methods:

• Proposed novel compact branches (three short branches and one ultra-compact branch) replacing conventional λ/4 and 3λ/4 branches.
• Incorporated an artificial neural network (ANN) with a radial basis function (RBF) network to optimize resonator performance.
• Simulated and fabricated the compact microstrip rat-race coupler design.

Main Results:

• Achieved a size reduction of over 82% compared to conventional coupler structures.
• Successfully suppressed the 2nd to 5th harmonics, improving device performance.
• Demonstrated the effectiveness of the proposed compact branches and ANN optimization.

Conclusions:

• The novel compact microstrip rat-race coupler offers significant size reduction while maintaining or improving performance.
• The integration of ANN with RBF networks provides an effective method for optimizing microwave components.
• This design presents a viable solution for applications requiring miniaturized and high-performance couplers.