A low‐insert loss and high‐return loss bandpass filter based on cut‐off rectangular waveguide for satellite communication application

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: Fabrication Of the Wg Zor Bpf And Testing The Prototypementioning

confidence: 93%

Section: Fabrication Of the Wg Zor Bpf And Testing The Prototypementioning

confidence: 99%

Section: Fabrication Of the Wg Zor Bpf And Testing The Prototypementioning

confidence: 99%

See 1 more Smart Citation

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

Seo

et al. 2023

Sensors

“…Setting up the structure in the electromagnetic analysis software with the values for the geometrical parameters, the transmission and reflection coefficients are obtained as in Figure 7 d,e, which meets the design requirement. This is very different from cavity filters presented by [ 15 , 16 , 17 ] in terms of shape and length, and is physically realized as follows.…”

Section: Fabrication Of the Wg Zor Bpf And Test Of The Prototypementioning

confidence: 96%

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.

“…Furthermore, in [75] and [76] evanescent mode lters have been designed with direct-coupled resonant apertures, with the objective of extending the out-of-band performance and reducing the total length of the lter. More recently, an evanescent mode lter has been discussed in [77],…”

Section: Resonant Aperturesmentioning

confidence: 99%

New Wide-Band Capacitive Filter Structures in Rectangular Waveguide Technology With Enhanced Out-of-Band Response

Sullca¹

The main objective of this doctoral thesis is the development of new capacitive ltering structures in rectangular waveguide that are able to provide wide bandwidths in the passband and improve, at the same time, the out-of-band response. These new guided structures have been developed in order to oer new technological solutions for high-frequency microwave lters, with a variety of dierent transfer functions, addressing specically the needs of future telecommunication systems for both ground and space applications.In this context, therefore, we discuss in this document the study, design and manufacture of several types of microwave lter in rectangular waveguide that show a signicant improvement with respect to the state-of-the-art. The new solutions that we propose are obtained by introducing simple modications in the structure of classic microwave lters. Several techniques based on hybrid irises, stepped impedance resonators, staircase conguration and E-plane T-junctions with shorted stubs or manifold connections, are successfully used in order to meet the very demanding specications of future systems for both ground and space applications. Furthermore, an additional current challenge faced by all designers of microwave components is the need to reduce both their physical size and mass (or weight). To address this issue, we discuss in this document the use of resonant apertures in rectangular waveguide, introducing a new family of lters which can be used to implement complex single and dual-band transfer functions with signicant size and mass reduction.In the following chapters of this doctoral thesis, each subject is discussed in detail including the basic theoretical formulations, design procedures, the results of full-wave electromagnetic simulations, manufacturing considerations, and the measured performance of a number of prototypes. Excellent agreement is found in all cases between measurement and simulations, thereby fully validating both the novel structures discussed and their design procedures.