Analysis of 220-GHz Low-Loss Quasi-Elliptic Waveguide Bandpass Filter

A 220-GHz low-loss and wideband waveguide bandpass filter with fourth-order quasi-elliptic response is presented and analyzed in this letter. An electric cross-coupling realized by easily manufactured capacitive iris is introduced in the classical folded quadruplet topology. The prototype fabricated by conventional computer numerical control (CNC)-metal-milling technology exhibits meaningful results of an insertion loss of around 0.6 dB and a 3-dB fractional bandwidth of 9.8% centered at 214.3 GHz, which are in excellent agreement with the simulated ones. The effects of tolerance and surface roughness on the filter performance are discussed in detail. All the results indicate that the present CNC process can meet the accuracy and roughness requirement of such waveguide filter in WR-4 band.

[1]  Sheng-Cai Shi,et al.  WR-3 Band Quasi-Elliptical Waveguide Filters Using Higher Order Mode Resonances , 2017, IEEE Transactions on Terahertz Science and Technology.

[2]  M. Lancaster,et al.  Micromachined WR-3 waveguide filter with embedded bends , 2011 .

[3]  J. M. Rebollar,et al.  Low-Loss Elliptical Response Filter at 100 GHz , 2012, IEEE Microwave and Wireless Components Letters.

[4]  Kwang-Seok Seo,et al.  $W$ -Band Bandpass Filter Using Micromachined Air-Cavity Resonator With Current Probes , 2010, IEEE Microwave and Wireless Components Letters.

[5]  R. Cameron.  Advanced coupling matrix synthesis techniques for microwave filters , 2003 .

[6]  Michael J. Lancaster,et al.  SU-8 micromachined WR-3 band waveguide bandpass filter with low insertion loss , 2013 .

[7]  Wei Hong,et al.  Design and analysis of a terahertz bandpass filter , 2015, 2015 IEEE International Wireless Symposium (IWS 2015).

[8]  P. Siegel.  Terahertz Technology , 2001 .

[9]  Wen Wu,et al.  Cavity bandpass filters with quasi-elliptic response at 220GHz , 2016, 2016 IEEE International Conference on Microwave and Millimeter Wave Technology (ICMMT).

[10]  K. Sarabandi,et al.  Micromachined J-band rectangular waveguide filter , 2011, 2011 XXXth URSI General Assembly and Scientific Symposium.

[11]  B. Jingfu,et al.  G-band rectangular waveguide filter fabricated using deep reactive ion etching and bonding processes , 2012 .