The Simulation, Design and Implementation of Bandpass Filters in Rectangular Waveguides

Seo

et al. 2023

Sensors

In this paper, a novel method is proposed to effectively reduce the size of a waveguide bandpass filter (BPF). Because the metallic cavities make the conventional waveguide end up with a large geometry, especially for high-order BPFs, very compact waveguide-type resonators having metamaterial zeroth-order resonance (WG ZOR) are designed on the cross section of the waveguide and substituted for the cavities. While the cavities are half-wavelength resonators, the WG ZOR is shorter than one-eighth of a wavelength. A substantial reduction in the size and weight of the waveguide filter is observed as the resonators are cascaded in series through coupling elements in the X-band that is much longer than that in K- or Ka-bands. The proposed metamaterial filter is realized as a 3D-printed structure to be lighter and thus more suitable for low earth orbit (LEO) satellites. An X-band of 7.25–7.75 GHz is chosen to verify the method as the passband with an attenuation of 40 dB at 7.00 GHz and 8.00 GHz as the roll-off in the stopband. The BPF is manufactured in two ways, namely the CNC-milling technique and metal coating–added 3D printing. The design is carried out with a geometrical parameter of not 10−2 mm but rather 10-1 mm, which is good for manufacturers but challenging for component designers. The measurement of the manufactured metal waveguide filters reveals that the passband has about ≤1 dB and ≤−15 dB as the insertion loss and the reflection coefficient, respectively, and the stopband has an attenuation of ≤−40 dB, which are in good agreement with the results of the circuit and the simulation. The proposed filter has a length of 14 cm as the eighth-order BPF, but the conventional waveguide is 20 cm as the seventh-order BPF for the same area of the cross section.

Section: Introductionmentioning

confidence: 99%

“…Reducing their size is a crucial factor to saving on costs in developing and launching satellites. Choocadee and Akatimagool showed second- and third-order rectangular WG BPFs [ 3 ]. Typical-size cavities are combined in series through irises for channel selectivity.…”

Section: Introductionmentioning

confidence: 99%

Effective Size Reduction of the Metallic Waveguide Bandpass Filter with Metamaterial Resonators and Its 3D-Printed Version

Seo

et al. 2023

Sensors

“…In the satellite communication, high-frequency signals must be so strong that they can travel hundreds to thousands of kilometers when emanated from the antenna. The filters, like other passive components in the feed assembly of the antenna, are made out of metallic waveguides to ensure high Q-factors and endure high power and the heat [ 3 , 4 , 5 , 6 , 7 ]. This is why the structures are bulky and heavy.…”

Section: Introductionmentioning

confidence: 99%

“…Size-reduction of them is a crucial factor to cost-saving in developing and launching satellites. Sarun and Somsak showed second- and third-order rectangular WG BPFs [ 3 ]. Typical sized cavities are combined in series through irises for channel selectivity.…”

Section: Introductionmentioning

confidence: 99%

Channel Selectivity of Satellite Transponders with the Antenna Combined with a Size-Reduced Metallic Waveguide Bandpass Filter Having Thin Metamaterial Resonators

Seo

Shin

et al. 2023

Sensors

Global and intercontinental networking relies on satellite communication. Its wireless communication system always has antennas and their feed assembly comprising waveguides. This makes the satellite payload heavy and costly. In this paper, a novel method is proposed to effectively reduce the size of a waveguide bandpass filter (BPF). Because the metallic cavities make the conventional waveguide end up with a large geometry, especially for high-order BPFs, very compact waveguide-type resonators having metamaterial zeroth-order resonance (WG-ZOR) are designed on the cross-section of the waveguide and substituted for the cavities. While the cavities are half-wavelength resonators, the WG-ZOR is shorter than one eighth of a wavelength. A substantial reduction in size and weight of the waveguide filter is observed as the resonators are cascaded in series through coupling elements in the X-band much longer than K- or Ka-band. An X-band of 7.25~7.75 GHz is chosen to verify the method as the passband with attenuation of 40 dB at 7.00 GHz and 8.00 GHz as the roll-off in the stopband. The BPF is manufactured using the CNC milling technique. The design is carried out with geometrical parameters, not of the level of 10 μm, but the level of 100 μm, which is good for manufacturers but a big challenge for component designers. The measurement of the manufactured metal waveguide filter reveals that the passband has about ≤1 dB and ≤−15 dB as insertion loss and reflection coefficient and the stopband has ≤−40 dB as attenuation, which are in good agreement with the results of the circuit and simulation. The proposed filter has a length of 3.5 λg as the eighth-order BPF, but the conventional waveguide is 5 λg as the seventh-order BPF for the same area of the cross-section. This metamaterial BPF is combined with a horn antenna. The filter enables the wide-band antenna to distinguish the band of transmission from that of noise suppression. This channel selectivity is obviously observed by the filter integrated antenna test.

“…The simulation, design and implementation of bandpass filters in rectangular waveguides has been proposed (Choocadee et al, 2012). In this paper, the filters were simulated and designed by using a numerical analysis program based on the wave iterative method.…”

Section: Introductionmentioning

confidence: 99%

Circular and Periodic Circular Profiles in a Rectangular Cross Section Along the Straight Waveguide

Menachem

Tapuchi²

2015

APR

The first objective of this paper is to present a technique and a particular application to calculate the dielectric profile, the elements of the matrix, and its derivatives of the dielectric profile in the cases of circular and periodic circular profiles in the cross section of the rectangular straight waveguide. The second objective is to investigate the influence of the circular and periodic circular profiles on the output fields. The proposed technique relates to the method that is based on the Laplace and Fourier transforms, the inverse Laplace and Fourier transforms. This model is useful to predict the structure of the output fields for circular and periodic circular profiles in a rectangular metallic waveguide. The application is useful for straight waveguides in the microwave and the millimeter-wave regimes.