D. Grauerholz

Optimized Waveguide E-plane Metal Insert Filters For Millimeter-wave Applications

A design theory is described for rectangular waveguide metal insert filters that includes both higher order mode interaction and finite thickness of the inserts. Optimized design data for three- to five-resonator type filters with severaf insert thicknesses suitable for metal stamping and etching techniques are given for midband frequencies of about 15, 33, 63, and 75 GHz. Measured passband insertion losses of prototypes for mid-band frequencies of 15, 33, and 76 GHz are 0.2, 0.6, and 0.7 dB, respectively.

Theory and Design of Low-Insertion Loss Fin-Line Filters

A design theory is described for low-insertion loss fin-line filters that includes both higher order mode propagation and finite thickness of the dielectric substrate and the metallic fins. Design data for three-resonator type fin-line filters with several substrate thicknesses are given for midband frequencies of about 15, 34, and 66 GHz. The measured insertion losses in the passband are 0.25, 0.5, and 1.3 dB, respectively, for these three frequencies.

Optimum design of waveguide E-plane stub-loaded phase shifters

Broadband low-insertion-loss E-plane stub-loaded rectangular waveguide phase shifters are designed with the method of field expansion into normalized eigenmodes, which includes higher-order mode interaction between the step discontinuities. Computer-optimized three-stub prototypes of 90 degrees differential phase shift with reference to an empty waveguide of appropriate length, designed for R140-band (12.4-18 GHz) and R320-band (26.5-40 GHz) waveguides, achieve typically +or-0.5 degrees phase shift deviation within about 20% bandwidth. For two-stub designs, the corresponding values are about +2.5 degrees /-1 degrees and 17%. Both designs achieve minimum return loss of 30 dB. The theory is verified by measurements of a compact R120-band (10-15 GHz) waveguide phase shifter design example milled from a solid block, showing measured insertion loss of about 0.1 dB and about +2.5 degrees /-0.5 degrees phase error between 10.7 and 12.7 GHz. >

E-Plane Integrated Circuit Filters with Improved Stopband Attenuation (Short Papers)

Improved stopband attenuation is achieved by thick strips, by reduced waveguide sidewall dimensions, and by double planar integrated circuits. In contrast to thick strips which may cause high passband insertion losses and filters with reduced waveguide dimensions which require additional tapers, double planar E-plane integrated circuit filters combine the advantages of low costs, high stopband, and low passband insertion losses. Computer-aided design of a four-resonator Ka -band double metal insert filter achieves a calculated stopband attenuation between 40 and 60 GHz of more than 50 dB, the calculated minimum passband insertion loss is 0.43 dB (measured 1.8 dB). Higher order mode excitation and finite thicknesses of the inserts are included in the calculations.

W-Band Low-Insertion-Loss E-Plane Filter (Short Paper)

Computer-optimized design data for a four-resonator metallic E-plane filter are given with a midband frequency of about 94 GHz. The method of field expansion into suitable eigenmodes used considers the effects of finite insert thickness and higher order mode interaction. The measured minimum passband insertion loss of a metal filter prototype is 1.5 dB.

Low-Insertion-Loss Fin-Line Filters for Millimetre-Wave Applications

A design theory is described for low-insertion-loss fin-line filters with fin-line gap widths over the total height of the waveguide housing. The theory includes both higher order mode propagation and the finite thicknesses of the dielectric and the metallic fins. An evolution strategy synthesis method yields optimum design data for three- and five resonator-type fin-line filters with several substrate thicknesses. The midband frequencies chosen are about 13, 34, 66, and 75 GHz. Measured minimum insertion-losses in the passband are about 0.2 dB (13 GHz), 0.5 dB (34 GHz), and 1.9 dB (65 GHz) for three-resonator-type filters as an example.

E-Plane Integrated Parallel-Strip Screen Waveguide Filters (Short Papers)

A rigorous field theory design of a class of rectangular waveguide screen fiIters is presented which achieves improved attenuation in the upper stopband. The method of field expansion into suitable eigenmodes used considers the effects of the finite rectangular E-plane grid thickness and the mutual higher order mode interaction of the single screens. Calculated results up to 55 GHz show that the peak attenuation in the upper stopband for a Ka-band (26-40-GHz) two-resonators filter example with a midband frequency of f/sub 0/= 37 GHz is about 70 dB, whereas its planar circuit single-metal-insert counterpart reaches only about 34 dB. A Ku-band (12- 18-GHz) filter prototype with three metal-etched screens yields a measured passband insertion loss of 0.8 dB at about f/sub 0/= 17 GHz and a measured attenuation in upper stopband of about 50 dB up to 25 GHz.

Double Planar Integrated Millimeter-Wave Filter

A double planar integrated circuit filter is introduced, which achieves significant higher stop-band attenuation against higher frequencies than the common single planar circuit, especially for designs in the near of the waveguide band end. The theory is based on field expansion into suitable eigenmodes which allows direct inclusion of both higher-order modes and finite strip thickness. Computer optimized design data for a four-resonator Ka-band metal etched double planar integrated filter prototype provide minimum passband insertion-loss of 0.43 dB (measured: 1.8 dB) at 39.04 GHz and stopband attenuations of about 53 dB (measured: 48 dB) at 40 GHz, 100 dB at 50 GHz.

E-Plane Integrated Circuit Filters with Improved Stopband Attenuation (Comments)

In the above paper, in rows 1 and 2 of Table 1 on p. 1392, the optimized design data should read as given below. These data relate to the filter performances shown in Figs. 3 and 4 (midband frequency f/sub 0/ = 38.66 GHz). The data originally reportedl pertain to filters not presented in the figures, with a midband frequency of f/sub 0/ = 39.5 GHz.