A miniature coupled-line-based 3-dB directional coupler using GaAs PHEMT process

A novel complementary-conducting-strip CCS coupled-line CL design is proposed to achieve compact size by applying two-dimensional layout and standard gallium-arsenide GaAs thin-film technology. To obtain high coupling and satisfy the design rules of GaAs process, mixed-couple mechanism with edge and broadside coupling are also used. A CCS CL-based Ka-band 3-dB directional coupler is fabricated using WIN 0.15-µm GaAs pseudomorphic high electron mobility transistor technology. Experimental results show that the proposed directional coupler can cover the entire Ka-band 26-40 GHz with through and coupling of approximately 3.7±0.25 dB, and isolation of better than 13 dB. In addition, the phase difference between the two output ports is approximately 90i¾?±5i¾?. The occupied area of the prototype without I/O networks is only 220 × 220 µm2. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:21-26, 2016.

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