Balanced low-loss Ka-band μ-coaxial hybrids

Kenneth Vanhille, Dejan Filipović, Christopher Nichols, Daniel Fontaine, Wendy Wilkins, Erik Daniel, Zoya Popović

Research output: Chapter in Book/Report/Conference proceedingConference contribution

19 Scopus citations


Miniature hybrid couplers are designed in an air-filled microfabricated rectangular coaxial line technology for operation near 36 GHz. The size of the couplers is less than 2.7 mm by 2.7 mm in area and 420 μm in height Air-filled copper μ-coaxial cable provides less than 0.3dB/cm loss at Ka-band. Coaxial-to-CPW probe transitions on the ports provide means to perform 4-port VNA measurements with an external SOLT calibration. After implementing a de-embedding procedure, measurements show return loss and isolation better than 20 dB, with output amplitudes of 3.2 dB ±0.1 dB, and output phase differences of 90° ±2.0° from 34.5 to 36.5 GHz. The return loss and isolation minima are shifted in frequency as compared to the optimal output amplitude and phase frequency. This frequency difference is 1.5 GHz near 36 GHz with this technology, however branch line couplers using branch-length and reactive tee-junction compensation methods are presented. The improvement is experimentally verified; the frequency differences are 0.5 and 0.2 GHz for the two compensated designs.

Original languageEnglish (US)
Title of host publication2007 IEEE MTT-S International Microwave Symposium Digest
Number of pages4
StatePublished - 2007
Event2007 IEEE MTT-S International Microwave Symposium, IMS 2007 - Honolulu, HI, United States
Duration: Jun 3 2007Jun 8 2007

Publication series

NameIEEE MTT-S International Microwave Symposium Digest
ISSN (Print)0149-645X


Other2007 IEEE MTT-S International Microwave Symposium, IMS 2007
Country/TerritoryUnited States
CityHonolulu, HI


  • Coaxial couplers
  • Millimeter wave devices
  • Photolithography

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Balanced low-loss Ka-band μ-coaxial hybrids'. Together they form a unique fingerprint.

Cite this