Third Order U-Shaped Quasi-Reflectionless Bandpass Filter

Alkhuwaildi, Bahaa Hamzah; Alkhafaji, Nasr

doi:10.2528/pierc22061203

Cited by 2 publications

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“…As previously stated, after two bandpass filters have been designed at the necessary frequencies, they must be merged to create the diplexer structure seen in figure (12). This combination will have an impact on the matching.…”

Section: Results Of the Final Proposed Diplexermentioning

confidence: 99%

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Design of reconfigurable and adjustable diplexer with very high isolation for both (L, S) bands applications based on pseudocombline structure

Alabedi,

Makki,

Alkhafaji

2024

Preprint

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In this paper, a 5-pole reconfigurable and tunable diplexer with high isolation based on a pseudo-combline structure is designed and simulated. The proposed diplexer has two BPFs for both channels that operate at specific bands S (2 GHz) and L (3.5 GHz). A new class of feed section is proposed to increase the matching level between BPFs to make them operate at the desired frequencies. Varactor diodes are used to obtain the tunability property for the proposed diplexer, where they can tune the two bands of the diplexer to different frequencies. Also, for reconfigurability, a pin diode can be used as a switch in the feed section between to BPFs. The proposed diplexer has a compact size (46.12*40.49) mm; the insertion loss of two channels is 0.86, 0.39 dB; and the return loss is 12.24, 18.47 dB. Finally, the proposed diplexer has the highest isolation between TX and RX ports (more than 69 dB), which is higher than other related works.

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Section: Results Of the Final Proposed Diplexermentioning

confidence: 99%

“…The tapping position is denoted by the electrical distance (Tp) from the shorted end of the input/output resonator [12]:…”

Section: -1-1-design Of the Pseudo-combline Bpfsmentioning

confidence: 99%

Design of reconfigurable and adjustable diplexer with very high isolation for both (L, S) bands applications based on pseudocombline structure

Alabedi,

Makki,

Alkhafaji

2024

Preprint

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Five-pole wideband quasi-reflectionless interdigital BPF with second harmonic suppression

Alabedi,

Vahab AL-Din Makki,

Alkhafaji

2024

Eng. Res. Express

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In this paper, a 5-pole quasi-reflectionless (QR) interdigital BPF with a wide range of non-reflecting signals is proposed, offering good impedance matching. Two absorptive T-shaped stubs are placed at the input and output ports of the interdigital BPF. The absorptive stubs are optimised to obtain the reflection as low as possible for a wide range. Additionally, we shift the adjacent resonators of the interdigital BPF up and down to improve overall performance. The design follows a specific procedure in order to investigate factors affecting the performance. Firstly, the convetional interdigtial bandpass filter is designed relying on the coupling matrix method. Next, we study the conversion of the stopband filter into an absorptive stub. The input impedance of the stub plays a vital role in determining the reflection bandwidth, so it is optimised as well. Meanwhile, the interdigital BPF and one abosrptive stub are combined, where the bandwidth of reflectionless becomes wider compared to the conventional interdigital BPF. Another absorptive stub is added into the other port of the BPF to make the proposed filter symmetric. Different orders of the interdigital PBF are analysed, where the fifth order has the best response. The proposed filter is fabricated and tested, and an FR4 substrate with a thickness of 1.5 mm and a dielectric constant of 4.5 is utilized. The simulation and measurement results agree well. The realised S11 is less than -10dB from 0.72GHz to 4.1GHz (i.e., -10dB reflectionless bandwidth 3.38GHz), while the realised S11 is less than -3dB from 0.42GHz to 6GHz (i.e., -3dB reflectionless bandwidth 5.58GHz). The S21 response is good for the transmission band. Finally, some slots are etched out from the gorund to reduce the influence of the second harmonic response.

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Third Order U-Shaped Quasi-Reflectionless Bandpass Filter

Cited by 2 publications

References 0 publications

Design of reconfigurable and adjustable diplexer with very high isolation for both (L, S) bands applications based on pseudocombline structure

Design of reconfigurable and adjustable diplexer with very high isolation for both (L, S) bands applications based on pseudocombline structure

Five-pole wideband quasi-reflectionless interdigital BPF with second harmonic suppression

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