Compact All-metal In-line Combline Coaxial Cavity Diplexer

Authors

DOI:

https://doi.org/10.26636/jtit.2024.4.1783

Keywords:

cavity, combline resonators, diplexer, L band

Abstract

This article describes the design of an all-metal combline coaxial cavity diplexer. The device is based on a Y-shaped star-resonant junction which allows to achieve a compact design by positioning the two channels in an in-line and side-by-side arrangement. The channels share the same geometry and are tuned to resonance using screws. The device was designed using the coupling matrix method. For verification, a combline cavity diplexer was manufactured and tested for E1 Galileo (1559-1591 GHz) and Iridium (1606-1638 GHz) applications with fractional bandwidth equaling 2% for both channels. The order and the return loss of each channel are 5 and 19.4 dB, respectively. The volume is 154.1 × 36 × 27.8 mm³, corresponding to a normalized volume of 0.810 × 0.189 × 0.146 λ³. The normalized volume per resonator is as low as 0.0047 λ³, while isolation is better than 55 dB. The ratio between the unloaded quality factor and the normalized volume per resonator is as high as 19.8 × 10⁴ λ⁻³. The design is very easy to manufacture, since it is all-metal and has a simple geometry.

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2024-12-31

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No. 4 (2024)

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Copyright (c) 2024 Giacomo Giannetti, Stefano Maddio, Enrico Boni

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How to Cite

[1]
G. Giannetti, S. Maddio, and E. Boni, “Compact All-metal In-line Combline Coaxial Cavity Diplexer”, JTIT, vol. 98, no. 4, pp. 9–14, Dec. 2024, doi: 10.26636/jtit.2024.4.1783.