Dual Band Bandpass Filter Using Meandered Ring Resonator

Dual Band Band yield Filter Using Meandered Ring resonant circuitDual deal anchor pack overturn puree apply Meandered mob resonator employ rigorous DGSMariselvam V, Raju SAbstract shove microstrip dual- band band twirl permeate (DBBPF) with high selectivity and near(a) suppression for wireless local ara nedeucerks (wireless local area networks) is proposed utilizing a novel plant scheme resonator nonsensical ring resonator DGS. cardinal passbands argon produced by a pair of plant half-wavelength meandered stepped- underground resonator (MSIR) and a quaternary wavelength short stub mean stepped- resistance resonator (SIR) separately. The freight rateed DGS avoids the cross lambast in the pass band which is useful to earn very sapiently cutoff in the pass band. The resonator is fed by folded T Shaped capacitive source-load pair microstrip feed business concern, and four infection zeros be obtained at both sides of the bands to improve selectivity and suppressi on. Simultaneously, the size of the filter is extremely shove because embedding half-wavelength MSIR only changes the interior material body of quad-wavelength SIR. To affirm the rule method, the knowing filter is fabricated and measured. Both simulated and measured results indicate that good infection property has been achieved.KeywordsLow-pass filter, spurious rejection, linear phase, ring resonators, microstrip filters microwave filters.1. IntroductionBPFs ar important block in RF front-to-end and throw away drawn practically attention since they can reject the useless signals. In 13, miniaturized BPFs with high selectivity and heighten out-of-band performance argon designed for wireless communication corpses. In late(a) years, with the development of different wireless standards, such as global system for mobile communication (GSM), wireless local-area ne bothrk (WLAN) and world interoperability for microwave glide path (WiMAX), designing multi-band BPFs with miniatu rized size, high selectivity and controllable frequencies has become a trend. In 46, pack and high selectivity dual-band BPFs are designed by ii sets of resonators, stepped-impedance resonators (SIR) and stub-loaded resonators, one by one. For dual-band BPF designs, various approaches have been studied. A simple effective method is to utilize two or three sets of resonators 710. In 7, a high selectivity dual-band BPF is designed by exploitation join stepped impedance resonators. Each set of resonators operates at a pass band, resulting in controllable frequencies. Unfortunately, it has large size due to the multi-sets of resonators. In this a novel Meandered stepped impedance resonator with loaded DGS is utilized to achieve the desire dual pass band and the size is reduced. The two passbands are generated by respective resonators. High selectivity is obtained by the introduction of several finite attenuation poles in stopband. Compared with the conventional dual band filter, the filter is pettyer in size and better in performance.2. Analysis of stepped impedance resonatorTo design a DBBPF utilise SIRs, the properties of SIR must be analyzed first. As shown in Fig. 1, the basic structure of half-wavelength SIR consists of two lines of different characteristic impedances Z1 and Z2 and electric lengths 1 and 2. It can be treated as two uniform cells (cell A and cell B). The vibrancy conditions can be obtained from one of them since the half-wavelength SIR is symmetrical 10. The impedance of the resonator can be calculated as expression harmonise to the above equation, the resonance appears when Zin is infinite, namely the denominator is equal to zero. As a result, the quest expression can be obtained as the resonance conditionWhere Rz is the impedance ratio. In expression (2), we can see that the resonance conditions are dictated by 1, 2 and Rz. It can adjust these three factors to obtain the resonance that we required, and a dual mode filter can be de signed by utilize SIR.Fig. 1.Basic structure of the half wave length SIR (3)s1 is the electrical length for the first spurious frequency fs1 .In this paper is to design a good WLAN filter, the first spurious frequency must be avoided at the designed lower passband.3. Design of DBBPFFig. 2 shows the transformation offshoot to design an embedded-scheme resonator for DBBPF. In Fig.2 (a) a quad-wavelength short stub loaded SIR is shown. To reduce its size, the SIR is folded as an open-loop. Additionally, the low impedance lines of quad-wavelength short stub loaded SIR are broad enough to provide area for a small resonator, which make it possible to embed a pair of small dyad resonators. So, we replace the low impedance lines with a pair of meandered SIRs, which is shown in Fig. 2(b). To achieve a high performance dual-band filter, it is necessary to introduce transmission zeros at both sides of the bands. Due to the existence of DGS, magnetic coupling takes up overabundant position on the short stub loaded SIR shown in Fig. 2(a). On the other hand, as the embedded MSIR is folded as an open-loop, it has the maximum electric content density at the side with an open gap, and the maximum magnetic domain of a function density at the opposite side. If the sides with the maximum magnetic field of two coupled resonators are proximately placed, the magnetic coupling can be obtained. Therefore, the coupling between the half wavelength SIR loops is also magnetic 15. So, transmission zeros near the two pass bands can be generated by feeding microstrip feed line with capacitive source-load coupling, which because the counteraction between electric field and magnetic field. These transmission zeros have permits to improve selectivity and suppression of this filter.(b)Fig. 2.Embedded Resonator DBBPF design scheme.A filter proposed for WLAN is shown in Fig. 4.A set of parameters of it is given in Tab.1.4. Filter conditionFig.3.T shaped stub loaded resonatorFig. 2 shows the configuration of the proposed micro strip dual-band BPF. It is composed of two sets of resonators. The outside resonators are stub-loaded resonators operating at the first and two pass band frequencies, i.e., 3.68 GHz and 7.01 GHz. Fig.3 illustrate the configuration of the resonator. It consists of a transmission line of length and a T-shaped stub loaded at the line centre is the overall length of the lines, namely L.L= B1+2d1+2f1+2C2+s1+2f1Open-circuited coupled-lines with the length C2and gap C1 are employed to realize electrical coupling. Two transmission lines with the characteristic impedance of 50 are connected to the outer resonators, acting as input and output ports. Embedded between the two outer resonators, the inner resonators 2 and3 are utilise to yield the aid pass band at f2. The inner resonators are fed by the outer ones. Using this structure, multi-path coupling can be realized for the pass band, which can help generate a pair of transmission zeros.(a)(b)Fig. 4. schematic view of the proposed filter (a) Top view (b) Bottom view5. CSRR DGS unitThe Ring Resonator structures are designed and produced by applying the Babinet principle to the recrudesce ring resonators (SRR). In this way structures with apertures in metal surface are obtained and these CSRRs create negative instead of negative in a peg range near the resonance frequency. In microstrip technology, left handed Metamaterial structures exhibiting band stop behaviour can be implemented by print CSRRs in the ground plane, underneath the conductor strip, and along the series capacitive gaps. The gap provides a negative value of the effective permeability up to certain frequency that depends on gap dimensions and separation. The negative structure has been obtained by loading a microstrip line with CSRR pinpoints as shown in Fig.4. There are many different parameters that affect resonance frequency of CSRR, most prevalent being the permittivity of the substrate and length of t he resonator. The resonance frequency is inversely proportionate to the length of the resonator and is directly proportional to the shatter gap of the resonator. It is considered that the CSRR particle is etched only in the ground plane. CSRR etching depth decides the intensity level of the resonance increases 12-13 In order to improve the frizzlyer cut-off, compact in size and harmonic suppression ability of the conventional dual band pass filter a CSRR is loaded in the bottom of the filter. The CSRR is designed at the anti-resonance frequency. Inherent nature of anti-resonance behaviour, it rejects the frequencies above cut-off frequency. In this way we achieved sharp cut-off.the dimensions of the ring resonator is given in Table.1.6. assumed and measured resultsTo validate the characteristics, the proposed dual band filter is fabricated and measured in a FR4 substrate with a relative dielectric constant 4.4 a onerousness of 1.6mm has been used in this paper. 50 ohms microst rip feed line with a largeness of 2.2mm is located at both of the input and output ports.fig 6 shows the photograph of the fabricated dual band filter. Fig.7. depicts the simulated and measured results of the proposed filter simultaneously. hither CST microwave studio is used for simulation and an Agilent network analyser N5230A is used for measurement. The simulated / measured minimum insertion losses are 0.65/0.985dB respectively at 3.684GHz band and 0.98/1.35dB respectively at 7.01 GHz. The size of the proposed layout is 14.5mmX19.9mm.(a)(b)Fig.6. Photograph of the range of dual- band filter (a) top view (b) bottom view(a)(b)Fig.7. Simulated and measured (a) S11 (b) S21 of the proposed filterTab. 1.Parameters of the proposed filterTab. 2.Comparison of the proposed filterIL-insertion lossFBW- aliquot Band width7. ConclusionIn this paper, a dual band filter designed by embedded resonator loaded with ring resonator DGS was presented. 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