Stepped Impedance Microstrip Directional Coupler With High Directivity Performance

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Apisak Worapishet


A directional microstrip coupler utilizing the stepped impedance coupled lines to equalize the even- and odd-mode phase velocities for directivity enhancement is investigated. The stepped impedance coupler features simple analysis, design, and implementation, with small area requirement, no use of lumped reactive components, and no via holes. Experimental results demonstrate a performance improvement in terms of the directivity by as large as 48.6 dB over the conventional coupler.

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