The E-Band contactless flange was incorporated into a pair of VNA frequency extenders, which were mounted on sliding rails to create a fast measurement system (see Figure 5). With this configuration, a DUT can be quickly inserted and removed for testing, offering the possibility for automated measurements when testing components in large quantities.

Figure 5

Figure 5 Using the CWF with a pair of VNA extenders that slide on rails enables the DUT to be easily inserted and removed while maintaining test port alignment.

Figure 6

Figure 6 Measured insertion loss of an E-Band isolator (a), directional coupler (b) and a different directional coupler (c).

Using this measurement system, the E-Band CWF was used to measure the insertion loss of an isolator and two different directional couplers, and the results were compared with the measurements made using conventional flanges (see Figure 6). The results show differences of less than 0.1 dB between the two setups, confirming that CWF can achieve reliable measurement results. The insertion loss measurements were repeated five times, achieving the same results in all cases.

CWF designs are being developed for waveguide sizes ranging from WR28 to WR05, covering the waveguide frequency bands from 26.5 to 220 GHz. Increasing demand for waveguide components in greater quantities will motivate more manufacturers to adopt CWF for their test systems, to increase productivity and reduce operator fatigue and possible errors in high volume production environments.


  1. A. R. Kerr, “Mismatch Caused by waveguide Tolerances, Corner Radii, and Flange Misalignment,” National Radio Astronomy Observatory, Tech. Rep. Electronics.
  2. Division Technical Note No. 215, 2010, [Online],
  3. P.-S. Kildal, “Three Metamaterial-based Gap Waveguides between Parallel Metal Plates for mm/submm Waves,” 3rd European Conference on Antennas and Propagation, Berlin, Germany, March 2009.
  4. E. Rajo-Iglesias and P.-S. Kildal, “Numerical Studies of Bandwidth of Parallel-plate Cut-off Realised by a Bed of Nails, Corrugations and Mushroom-type Electromagnetic Bandgap for use in Gap Waveguides,” IET Microwaves, Antennas & Propagation, Vol. 5, No. 3, February 2011, pp. 282–289.
  5. E. Pucci and P.-S. Kildal, “Contactless Non-leaking Waveguide Flange Realized by Bed of Nails for Millimeter Wave Applications,” Proceedings of the 6th European Confence on Antennas and Propagation (EUCAP), May 2012, pp. 3533–3536.
  6. R. Naruse, H. Saito, J. Hirokawa and M. Zhang, “Non-contact Wavefeed with Choke-flange Waveguide at the Development Section of the Expansion Antenna for Small Satellite,” IEICE, Tokyo, Japan, Tech. Rep. SANE 2014-61, Vol. 114, No. 194, August 2014, pp. 77–82.
  7. X. Chen, W. Cui, etc. “Low Passive-Intermodulation Contactless Waveguide Adapter Based on Gap Waveguide Technology,” 13th European Conference on Antennas and Propagation Conference, 2019.
  8. P.-S. Kildal, E. Alfonso, A. Valero-Nogueira and E. Rajo-Iglesias, “Local Metamaterial-based Waveguides in Gaps between Parallel Metal Plates,” IEEE Antennas Wireless Propagation Letters, Vol. 8, April 2009, pp. 84–87.
  9. H. Li, A. Arsenovic, J. L. Hesler, A. R. Kerr and R. M. Weikle, “Repeatability and Mismatch of Waveguide Flanges in the 500–750 GHz Band,” IEEE Transactions on Terahertz Science and Technology, Vol. 4, No. 1, January 2014, pp. 39–48.
  10. D. Sun, Z. Chen and J.Xu. “Flexible Rectangular Waveguide based on Cylindrical Contactless Flange,” Electron Letters, Vol. 52, No. 25, December 2016, pp. 2042–2044.
  11. D. Sun and J. Xu. “Real Time Rotatable Waveguide Twist Using Contactless Stacked Air-Gapped Waveguides,” IEEE Microwave and Wireless Components Letters, Vol. 27, No. 3, March 2017, pp. 215–217.