A Miniaturized 3 dB Branch-Line Hybrid Coupler With Harmonics Suppression

作者：Tsai Kai Yu^*; Yang Hao Shun; Chen Jau Horng; Chen Yi Jan Emery

来源：IEEE Microwave and Wireless Components Letters, 2011, 21(10): 537-539.

DOI：10.1109/LMWC.2011.2164901

• Hybrid
• microstrip coupler
• microwave circuits
• miniaturization technique

This letter presents a miniaturized 3 dB branch-line hybrid coupler with second harmonic suppression using high-impedance transmission lines and interdigitated shunt capacitors. By using the interdigitated capacitors shunt with the transmission lines, further minimization of the 3 dB branch-line hybrid coupler can be achieved compared with previously reported techniques. The design of the interdigitated shunt capacitors requires concurrent optimization of the capacitance to the ground and the edge-coupling interdigitated capacitance between the ports. For validation, a miniaturized 3 dB branch-line hybrid coupler at 836.5 MHz was designed and implemented. The proposed 3 dB branch-line hybrid coupler achieved a compact size of 27.75 mm x 25.7 mm, or equivalently 0.077 lambda(o) x 0.072 lambda(o), where lambda(o) is the free-space wavelength. Moreover, the coupler can suppress second harmonic components by 20 dB while maintaining similar measured performance compared to the conventional branch-line hybrid coupler.

• 出版日期2011-10
• 单位中国科学院电工研究所