A New Synthesis and Design Approach of a Complex Termination Impedance Bandpass Filter

An impedance transformer (IT) with wideband and high selectivity is presented in this paper. Three transmission poles were obtained within the passband and provides a wide passband response. Moreover, there are two transmission zeros (TZs) close to the passband that were achieved by a shunt parallel coupled line and provide high selectivity. For validation of proposed circuit, the ITs were designed at a center frequency (f0) of 3.5 GHz using an impedance‐transforming ratio (r) of 5 and 10. For r = 5, |S21| and |S11| are 0.36 dB and 28 dB at f0, respectively. Within the passband, |S21| and |S11| are better than 0.65 dB and 18 dB, respectively. The TZs at 2.65 GHz (0.76f0) and 1.22f0, close to the passband, were measured with attenuation better than 37 dB. The out‐of‐band attenuations are higher than 20 dB from DC to 2.77 GHz of the lower stopband and from 4.16 GHz to 9.73 GHz of the higher stopband. For r = 10, |S21| = −1.4 dB and |S11| = −23 dB were measured at f0. An 18 dB return loss was obtained from 3.415 GHz to 3.694 GHz (FBW = 7.96%).

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“…The overall circuit sizes are 24 mm × 22 mm (0.28 λ 0 × 0.26 λ 0 ). The method used to measure the proposed IT is mentioned in reference [13].…”

Section: Simulation and Measurement Resultsmentioning

confidence: 99%

High selectivity and wideband bandpass filtering impedance transformer

Kim

Jeong

2021

Int J RF Microw Comput Aided Eng

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“…The parallel‐coupled lines are equivalent to J ‐inverters, whereas the T‐type TLs are equivalent to K ‐inverters. Using filter theory, the values of J‐ and K ‐inverters are determined 25 as (1).

J_{01} goodbreak= \sqrt{\frac{Re (Y_{inS}) Δ b}{g_{0} g_{1}}}

K_{12} goodbreak= \frac{normalΔ x}{\sqrt{g_{1} g_{2}}}

J_{23} goodbreak= \sqrt{\frac{Re (Y_{inL}) Δ b}{g_{2} g_{3}}}

where g i ( i = 0, 1, 2, 3), ∆, b , and x are low‐pass prototype‐element values, fractional bandwidth, susceptance slope parameter and reactance slope parameter of tunable resonator, respectively. Similarly, Re( Y inS ) and Re( Y inL ) are the real part of input impedance looking at the first and last inverter as shown in Figure 1B, respectively.…”

Section: Analytical Analysismentioning

confidence: 99%

“…The parallel-coupled lines are equivalent to J-inverters, whereas the T-type TLs are equivalent to K-inverters. Using filter theory, the values of Jand K-inverters are determined 25 as (1).…”

Section: Proposed Structure Of Impedance Transformermentioning

confidence: 99%

A design of impedance transformer with tunable center frequencies using filter synthesis approach

Chaudhary

Jeong

2022

Int J RF Mic Comp-Aid Eng

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Microwave impedance transformer (IT) with center frequency tunable capability is one of great research issue for better utilization of frequency spectrum resources and system miniaturization of next generation wireless communication systems. This article presents a filter synthesis approach for designing IT with center frequency tunable capability using single dc-bias controlled tunable resonators. The proposed IT provides bandpass filtering response and is designed by properly coupling quarter-wave tunable resonators with alternate J-and K-inverters. The J-inverters are realized using a parallel-coupled line, whereas K-inverter is implemented with T-type short-circuited TL. Using filter theory, analytical design equations are derived to calculate the circuit parameters. The center frequency of the proposed IT is tuned over a wide frequency tuning range (FTR) by changing the varactor diode capacitance of quarterwave resonators. For experimental demonstration, a prototype of 25-to-50 Ω IT is designed, simulated, and measured. The measured results confirmed that the center frequency of the proposed IT is tuned from 2.05 to 2.91 GHz (860 MHz or 34.68% FTR) with an insertion loss variation of 2.57 to 1.76 dB.

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“…The BPF consisted of the multi-stage parallel-coupled TLs with different even-and odd-mode impedances. Recently, ATI BPF matching networks using λ/4 stepped impedance resonators were proposed in [4]. The structure consisted of open-ended parallel-coupled TLs and T-type TLs that were cascaded alternately.…”

Section: Introductionmentioning

confidence: 99%

Substrate Integrated Waveguide Quasi-Elliptic Filter with Arbitrary Termination Impedances

Pech

Kim

Chaudhary

et al. 2022

J Electromagn Eng Sci

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This paper presents a quasi-elliptic filter (QEF) with arbitrary termination impedances (ATI). The proposed QEF is designed by adding cross-coupling between the first and last resonators of an ATI bandpass filter (BPF) with the Chebyshev response. The proposed QEFs with ATI can be designed in even-order resonators and the location of the pair transmission zeros (TZs) is controllable. To prove the validity of the proposed design, the fourth-order QEFs with ATI were implemented on a single-layer substrate-integrated waveguide (SIW) cavity at a center frequency (f0) of 10 GHz with the pair TZs at 10 ± 1.4 GHz. These SIW QEFs with ATI improve frequency selectivity and effectively suppress the out-of-band signal with high power handling. The measured maximum insertion loss (|S21|) and minimum return loss (|S11|) of the SIW QEF with unequal real-to-real ATI are 0.93 dB and 17.4 dB, respectively, in the passband. Similarly, the maximum |S21| and minimum |SS11| of the SIW QEF with complex-to-real ATI are 1.2 dB and 18 dB, respectively.yer substrate-integrated waveguide (SIW) cavity at a center frequency (

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A New Synthesis and Design Approach of a Complex Termination Impedance Bandpass Filter

Cited by 14 publications

References 27 publications

High selectivity and wideband bandpass filtering impedance transformer

High selectivity and wideband bandpass filtering impedance transformer

A design of impedance transformer with tunable center frequencies using filter synthesis approach

Substrate Integrated Waveguide Quasi-Elliptic Filter with Arbitrary Termination Impedances

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