Compact Microstrip Bandpass Filter With Multispurious Suppression

Wu, Hung‐Wei; Liu, Shih-Kun; Weng, Min‐Hang; Hung, C.-Y.

doi:10.2528/pier10061601

Cited by 26 publications

(23 citation statements)

References 10 publications

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“…The reason is caused by the second harmonic of the fundamental passband, which locates too close to the new passband. To suppress the second harmonic of the fundamental passband, another four shunt short stubs are added [21,22], as shown in Fig. 2(c).…”

Section: Dual-band Filter Designmentioning

confidence: 99%

An Approach for Multi-Band Bandpass Filter Design Based on Asymmetric Half-Wavelength Resonators

Wang²

2013

PIER

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Abstract-This paper presents that the extra passband with two transmission zeros can be obtained by adding shunt open stubs to the asymmetric half-wavelength resonators structure. By using this method, a fourth or even higher passband with good selectivity and compact size can be obtained. Dual-band, tri-band and quad-band bandpass filters are demonstrated by using this method. The measured bandwidth is 80/180 MHz for the dual-band, 60/180/180 MHz for the tri-band and 130/360/170/70 MHz for the quad-band filter, respectively. The measured insertion loss for the dual-band, tri-band and quad-band filter is less than 2.7 dB, 2.5 dB and 2.9 dB at the center frequency. All the simulated results and the measured results agree well.

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Section: Dual-band Filter Designmentioning

confidence: 99%

An Approach for Multi-Band Bandpass Filter Design Based on Asymmetric Half-Wavelength Resonators

Wang²

2013

PIER

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“…Firstly, since the design parameters of SIRs have been properly designed, the resonators in CM half-circuit also have the resonances misaligned/staggered (including fundamental one) and thus the transmissions are reduced at individual resonance of each SIR [19,20]. It is worth mentioning that microwave signals transmit along the filter structure even the adjacent resonators do not resonate at the same frequency.…”

Section: Common-mode Designmentioning

confidence: 99%

Stopband-Extended Balanced Filters Using Both Λ/4 and Λ/2 Sirs With Common-Mode Suppression and Improved Passband Selectivity

Lin¹,

Yeh²

2012

PIER

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Abstract-Benefitting from the simultaneous utilization of quarterwave (λ/4) and half-wave (λ/2) microstrip resonators, a via-free balanced bandpass filter (BPF) with direct-coupled scheme is presented in this study. In the beginning, a single-ended filter with transmission zeros (TZs) is newly proposed and the mechanism of creating two TZs around the passband without necessitating cross couplings is adopted. The TZs can be made structure-inherent based on the coexisted out-of-phase couplings among a coupled-resonator pair. On the foundation of the presented single-ended filter, a balanced filter featuring extended differential-mode (DM) stopband, good commonmode (CM) suppression, and improved passband selectivity has been designed and implemented. The DM stopband extension is achieved by misaligning the higher-order harmonic frequencies of each resonator in the DM bisected circuit while the CM suppression is accomplished by both harmonic misalignment and careful designed coupled structure in the CM bisected circuit. Eventually, a demonstrated balanced filter centering at 1.5 GHz possesses DM stopband extended up to 8f d 0 , where f d 0 denotes the DM operation frequency, and its CM rejection ratio (CMRR) within DM passband better than 51.9 dB is attained. For measurement convenience, the DM characterizations have been accomplished by 2-port network analyzer with simple rat-race baluns and are found relatively accurate within the −15 dB bandwidth of the utilized baluns.

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“…6 is terminated by reference impedance (Z 0 ) the output impedance of (Z out λ/4 ) and (Z out coupling ) are simply found by substituting (14) and (25) into (23), (24). The computed results are shown in Figs.…”

Section: Symmetrically Coupled Port Feeding Networkmentioning

confidence: 99%

“…3 shows the transmission line model of the branch line coupler with quarter-wavelength feeding networks. (14) shows the ABCD matrix of the quarter-wavelength transmission line network, where Z T and θ T are the characteristic impedance and electrical length respectively of the feeding network. This matrix is used to obtain the theoretical response.…”

Section: Quarter-wavelength Port Feeding Networkmentioning

confidence: 99%

“…However, Sun and Zhu [12] reported several drawbacks including narrow passband bandwidth, tight coupling, high insertion loss, limited stopband and lower Q-factor. Some research works have been done to extend the stopband but invariably results in narrower passband bandwidth [13][14][15]. The multi-mode resonators [12] is an approach used to increase bandwidth to more than 100%, however it cannot improve the bandwidth of the other interconnected components.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multifolded Bandwidth Branch Line Coupler With Filtering Characteristic Using Coupled Port Feeding

Wong¹,

Zheng²,

Chan³

2011

PIER

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Abstract-A new uni-planar structure branch-line coupler with broad bandpass response is proposed. Single section branch line couplers (SSBC) are popular due to their simplicity and ease of use but suffer from narrow return loss bandwidth and poor out of band rejection characteristics. The work presented here overcomes these limitations with the use of coupled port feeding. Through the study of input impedance of feeding network and single section branch line coupler, the bandwidth of the new coupler increased by almost 6-times. In addition, the coupler exhibited band-pass filtering characteristics. Measured results exhibited low insertion loss (≤ 4-dB), small magnitude difference (≤ 1-dB), good return loss and isolation (≥ 10-dB) and small phase variation (90 • ± 5) within the passband. A measured bandwidth of 58% was achieved with this single section coupled port fed branch line coupler at a centre frequency of 1-GHz. Its two output ports achieved rejection levels better than 25 dB in the stopband.

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Compact Microstrip Bandpass Filter With Multispurious Suppression

Cited by 26 publications

References 10 publications

An Approach for Multi-Band Bandpass Filter Design Based on Asymmetric Half-Wavelength Resonators

An Approach for Multi-Band Bandpass Filter Design Based on Asymmetric Half-Wavelength Resonators

Stopband-Extended Balanced Filters Using Both Λ/4 and Λ/2 Sirs With Common-Mode Suppression and Improved Passband Selectivity

Multifolded Bandwidth Branch Line Coupler With Filtering Characteristic Using Coupled Port Feeding

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