A 24-44 GHz broadband subharmonic mixer with novel isolation-enhanced circuit

Chun Chi Su, Chien Hung Liu, Chih Ming Lin, Yi Lun Tsai, Yeong Her Wang

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9 Citations (Scopus)


A 24 to 44 GHz upconversion broadband subharmonic mixer with a novel isolation-enhanced architecture is presented through a 0.15 μm GaAs pHEMT process. Total chip size including probe pads is less than 1.33 × 0.82 mm2. The isolation-enhanced circuit is constructed from two directional couple lines both formed with three microstrip lines. They are used to enhance the isolation between IF/LO-to-RF and LO-to-IF. IF and RF pre-amplifiers are employed to achieve high conversion gain for subharmonic mixing of anti-parallel diode pairs. Based on the unilateral characteristics of an IF pre-amplifier, the LO/RF-to-IF isolations exhibit substantial improvement. From the measured results, the conversion gain of the mixer is 6.0 to 10.5 dB operating at RF frequency of 24 to 44 GHz. The IF-to-RF, LO-to-IF, LO-to-RF, and 2LO-to-RF isolations are 24.5 to 27.1 dB, 32.4 to 39.6 dB, 20.6 to 24.6 dB, and 48.4 to 65 dB, respectively.

Original languageEnglish
Article number7012115
Pages (from-to)124-126
Number of pages3
JournalIEEE Microwave and Wireless Components Letters
Issue number2
Publication statusPublished - 2015 Feb 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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