A K-band balanced subharmonically pumped image rejection mixer using 0.15-μm GaAs pHEMT technology

This work presents a K-band balance single side-band subharmonically pumped image rejection diode mixer (SHIRM).It uses lumped elements and three-conductor-line quadrature couplers and is fabricated in a 0.15-μm GaAs process. The SHIRM is realized in size reduction by using two antiparallel diode pairs for frequency mixing. The three-conductor-line bending coupler is 55% reduction in size compared to the nonbending one for radio frequency port, and lumped elements realization is 62% smaller in size than the quarter-wavelength line for local oscillator port. The proposed circuit with a symmetric layout provides good matches on amplitude and phase performances. The measured results exhibit a minimum conversion loss of 13 dB, a maximum image rejection ratio of 19 dB. All ports isolations are better than 10 dB. The chip area is only 1.5 × 1 mm².