New compact Ka-band CPW rat-race coupler using GaAs MMIC technology

作者：Chang C L^*; Tseng C H

来源：Electronics Letters, 2013, 49(19): 1227-+.

DOI：10.1049/el.2013.1478

• coplanar waveguides
• gallium arsenide
• high electron mobility transistors
• III-V semiconductors
• losses
• MIMIC
• MMIC
• waveguide couplers
• compact Ka-band CPW rat-race coupler
• MMIC technology
• RRC
• pHEMTs process
• asymmetrical coplanar-waveguide T-structure
• compact circuit footprint
• return-loss bandwidth
• short-circuited quarter-wave stub
• output phase response
• phase difference
• size 0
• 15 mum
• loss 10 dB
• frequency 28
• 73 GHz to 39
• 53 GHz
• gain-0
• 269 dB to 0
• 8 dB
• GaAs

A new compact Ka-band rat-race coupler (RRC) is proposed and fabricated in the 0.15-m GaAs pHEMTs process. Since the developed RRC is implemented by asymmetrical coplanar-waveguide T-structures, it has a compact circuit footprint and a return-loss bandwidth similar to that of the conventional coupler. Besides, a short-circuited quarter-wave stub is attached into the ring of the RRC to flatten the output phase responses. The developed coupler has a 47.28% 10-dB return-loss bandwidth and only occupies a 20.89% circuit size of the conventional one. By considering the 180 degrees +/- 5 degrees phase difference, the frequency range covers from 28.73 to 39.53 GHz with a 31.6% relative bandwidth. Over this frequency range, the amplitude imbalance varies from - 0.269 to 0.8 dB.

• 出版日期2013-9-12