volume | PIER Journals

Abstract

A new miniaturized microstrip branch-line coupler with good harmonic suppression is proposed in this paper. The new structure has two significant advantages, which not only effectively reduces the occupied area to 19.1% of the conventional branch-line coupler at 0.90 GHz, but also has high 7th harmonic suppression performance. The measured results indicate that a fractional bandwidth of more than 15.6% has been achieved while the phase difference between S₂₁ and S₃₁ is within 90° ± 0.8°. The measured fractional bandwidths of |S₂₁| and |S₃₁| within 3 ± 0.3 dB are 16.1% and 16.7%, respectively. Furthermore, the measured insertion loss is comparable to that of a conventional branch-line coupler. The new coupler can be easily implemented by using the standard printed-circuit-board etching processes and is very useful for wireless communication systems.

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Dr. Hai Zhang

Mr. Xiaolu Lu