A compact five-port waveguide structure and its application as a three-way power divider.

Area of Science:

• Electromagnetics and Waveguide Technology
• Microwave Engineering
• RF Circuit Design

Background:

• Waveguide structures are crucial components in microwave and RF systems.
• Efficient power division is essential for various applications, including radar and communication systems.
• Existing power dividers often face limitations in terms of size, bandwidth, or isolation.

Purpose of the Study:

• To propose and characterize a compact, wide-bandwidth five-port waveguide structure.
• To demonstrate its functionality as a reciprocal TEM mode-to-three-way TE10 mode power divider.
• To analyze its scattering matrix, matching properties, and performance metrics.

Main Methods:

• Derivation of the ideal scattering matrix based on structural symmetry.
• Design and implementation using coaxial probes, a frustum, and a coaxial transition for wideband matching.
• Theoretical analysis and experimental validation of the waveguide structure's performance.
• Characterization of return loss, isolation, and power division imbalances.

Main Results:

• The proposed five-port structure achieves automatic matching when the circular and coaxial ports are matched.
• Measurements show return losses greater than 20 dB (rectangular ports) and 17 dB (coaxial port) from 8 to 9.6 GHz.
• High isolation (> 20 dB) among the three rectangular ports is achieved.
• Amplitude and phase imbalances in power division are less than 0.1 dB and 2°, respectively.
• The structure exhibits a compact volume of 1.5λ × 1.5λ × λ.

Conclusions:

• The developed five-port waveguide structure is a high-performance, compact reciprocal power divider.
• The design offers wide bandwidth, excellent matching, and superior isolation characteristics.
• The theoretical and experimental results confirm the structure's viability for practical applications in microwave systems.