Dual-mode Ring Resonator Research Articles

Design of Novel Filtenna for Wireless Applications

In this paper, a novel design based on a dual-mode ring resonator, the filtering balun, feeding the printed dipole antenna, the filter balun antenna (FBA), is presented. One port on the structure allows the signals to be phase-shifted 180 degrees from one unbalanced port to two balanced signals. The suggested designs use a single dual-mode ring resonator to operate as both a filter and a balun at the same time. Compact designs are achieved by applying feeding to the second layer. Another unique characteristic of the filtering balun is its ability to alter, based on perturbation size, the phase error and magnitude imbalance of the two balanced signals. With the use of the Advanced Design System (ADS) software, numerous structures have been developed, modeled, and evaluated. To achieve the highest performance, every section of the design is assessed and optimized. Because the substrate is a lossy type (FR4), the realized transmission coefficients, which are poorer than expected ideal values, make the suggested design a strong contender for narrow-band wireless applications. For S2,1 and S3,1, the signal is routed through two viasand fed into a dipole antenna in the opposite phase by employing the zero iteration for filtering the balun in the first layer to condense with the second layers. The antenna structure is a printed dipole antenna operating at 2.4 GHz

Design of Miniaturized Microwave Filtering-Balun Component for Wireless Applications

This research paper introduces a new design being Minkowski-like fractal filtering-balun MLFFB based on the dual-mode ring resonator. The structure has three ports, converting the signal from one unbalanced port to two balanced ports (i.e., 180° phase shift). The proposed design can act as a filter and balun simultaneously using one dual-mode ring resonator. The fractal curves are applied to have compact designs. The 0th, 1st, and 2nd iterations of the Minkowski-like fractal curves are applied to demonstrate the miniaturization ratio obtained in the proposed work. The miniaturization ratios are 47.8% and 73% of the 1st iteration and 2nd iteration of the Minkowski balun-filtering components, respectively, compared to the 0th iteration. Also, the filtering balun has a distinctive feature, which is the control of the phase error and magnitude imbalance of the two balanced ports, depending on the size of the perturbation part. Several structures have been designed, modeled, and analyzed utilizing the Advanced Design System (ADS) software. Each design iteration is evaluated and optimized to attain the best performance. The operating frequency is 2.4 GHz, and the realized transmission coefficients are S21 = -7 dB and S31 = -6.5 dB, which are less than expected ideal values because the substrate is a lossy type, being FR4. The S11 is less than -10 dB. The proposed design is a good candidate for narrow-band wireless applications.

High Performance Balanced Bandpass Filters With Wideband Common Mode Suppression

Two compact and high selectivity balanced bandpass filters with excellent common mode rejection are designed in this brief. Compared with the half-wavelength microstrip transmission line, 180° phase shift is realized by two small swap structures, which are composed by double-sided parallel-strip line (DSPSL), and this way can easily realize a wideband common mode rejection with compact circuit size. Two out-of-band transmission zeros are introduced by the dual-mode ring resonator in the first proposed structure; thus, high selectivity can be achieved. In the second filter, shorted/open coupled microstrip lines are added between the dual-mode ring resonator and 180° swap structure, two additional transmission zeros can be achieved. Finally, two prototypes center at 2.2 GHz are fabricated, and the measured 3-dB bandwidths for the differential mode are 23.6% and 11.8%, respectively.

High-selectivity single-ended and balanced bandpass filters using ring resonators and coupled lines loaded with multiple stubs

High-selectivity single-ended and balanced bandpass filters (BPFs) using dual-mode ring resonators and coupled lines loaded with multiple stubs are proposed in this paper. With the help of the loaded short-circuited and open-circuited stubs, six deep transmission zeros (TZs) from 0 to 2f0 (f0: center frequency of the passband) can be realized in both of single-ended and balanced BPFs to improve the stopband suppressions. The functions of the loaded short/open stubs and calculated analysis of TZs’ positions have been presented. For further demonstration, two examples of single-ended BPF and balanced BPF with high common-mode suppression are designed and fabricated, whose center frequencies are both at 2.1 GHz. Their measured 3-dB fractional bandwidths are 23.7% and 24.7% (differential-mode), respectively. The simulated results and measurements of these two filters are in good agreement.

Self-coupled dual-mode ring resonator with turning transmission zeros in microwave bandpass filter for planar metamaterial: analysis and design

An H-shape dual-mode closed resonator with self-coupled segments is reported. The self-coupling between ring segments renders an equivalent mode perturbation effect as the normal ways of adding stub, cutting notch, or varying line impedance to the ring resonator. The mode perturbation and transmission-zero generation from the self-coupling effect and step-impedance were analyzed using the even–odd mode theory. By regulating the impedance ratio and coupling coefficients of self-coupled sections, the self-coupled ring resonator can produce either the capacitive or inductive perturbation. The input and output positions affect the number and locations of transmission zero. The positions of input and output ports are properly selected. In the capacitive perturbation case, when the two transmission zeros are located on both sides of the passband, and bring about a pseudo-elliptic bandpass response. The analysis of finding optimized taping positions of input and output ports is proposed. Comparing to the regular uniform ring resonator, the H-shaped self-coupled ring resonator has shorter ring length, is easily to be folded and does not destroy the dual-mode characteristics. The feature of compact size is favorable in the design of a bandpass filter. A 2.45-GHz bandpass filter based on the H-shaped self-coupled ring resonator was performed to verify the proposed theory. A schematic bandpass filter was implemented with a compact size which is only 20% of the conventional dual-mode bandpass filter.

인공전송선로를 이용한 이중모드 링-공진기 대역통과 여파기

Abstract This paper presents dual-mode ring-resonator bandpass filter using LUC of artificial-transmission-lines. The conventional ring-reso-nator bandpass filter has limitation in miniaturization because the conventional ring-resonator is based on a one wavelength operation, and problem due to undesire harmonics. The ring-resonator bandpass filter is miniaturized and show higher order mode rejection by configuring a ring-resonator with LUC of artificial-transmission-lines. The two-stage bandpass filter is designed and fabricated with a ring-resonator and input/output interdigital coupled line. A fabricated filter shows dual-mode, rejection of whole ultra wide band, sharp skirt characteristics and has ring area reduced by 60 % compared to the conventional ring-resonator bandpass filter.Key words: Artificial-Transmission-Line, LUC, Dual-Mode, Ring-Resonator, Higher Order Mode Rejection, Miniaturization, Ultra Wide BanddeC$2016fghi8fjfkeC7@l(mnop520150461)#A8' eCqrs.t i8fjBIT#uvRf(Department of BIT Medical & Electrical and Electronics Engineering, Kangwon National University)

Wideband filtering crossover using dual‐mode ring resonator

A wideband filtering crossover using a dual-mode ring resonator is proposed. Two half-wavelength open stubs are used to produce transmission zeroes for the crossover passband. A high selectivity wideband filtering crossover with a fifth-order passband is designed and fabricated for verification. The measured results and theoretical expectations have good agreement.

두 단락 스터브를 갖는 이중 모드 링 공진기를 이용한 WLAN용 이중대역 대역통과 여파기의 설계 및 제작

본 논문에서는 두 단락 스터브를 갖는 이중 모드 링 공진기를 이용하여 높은 신호 선택도를 가지는 이중대역 대역통과 필터를 제안하였다. 링 공진기의 이중 모드 공진을 위하여 두 피드 라인을 커플링 커패시터를 통해 비직교 급전 각도를 가지도록 연결하였다. 서로 다른 두 길이를 가지는 두 단락 스터브를 링 공진기의 두 대칭면에 위치시킴으로써 이중 대역을 지원하는 여파기를 설계할 수 있었다. 급전 각도 섭동을 준 링 공진기와 제안한 이중대역 대역통과 필터는 대칭 구조이므로 Even/Odd 모드 해석을 통하여 산란계수와 전송 영점 주파수들을 도출할 수 있다. 제안한 이중대역 대역통과 필터는 IEEE 802.11n 기준의 WLAN 어플리케이션에 적용 가능하도록 설계 및 제작되었다. 측정 결과와 시뮬레이션 결과가 잘 부합하였고, WLAN 응용뿐만 아니라, 향후 다른 통신시스템에도 적용이 가능하리라 판단된다. In this paper, A high selective dual-band bandpass filter was proposed using a dual-mode ring resonator with two short-circuited stubs. For dual-mode resonance, the ring resonator is directly connected with non-orthogonal feed-lines via coupling capacitors. Two short-circuited stubs which are unequal lengths are simultaneously placed at two corners along the two symmetry plane of the ring resonator in order to obtain dual-band responses. Because the feeding angle perturbated ring resonator of the proposed dual-band bandpass filter has the symmetrical structure, Even/Odd mode analysis can be well applied to extract the scattering parameters and transmission zero frequencies. The proposed dual-band bandpass filter was designed and fabricated for WLAN(Wireless Local Area Network) application of IEEE 802.11n standard. The measured results showed a good agreement with the simulation results, and it should be well applied not only for WLAN applications but also for any other communication systems.

Differential bandpass filter on dual‐mode ring resonator with slotline feeding scheme

A new dual-mode differential bandpass filter on a squared microstrip ring resonator with a slotline feeding scheme is presented. This filter consists of a microstrip dual-mode ring resonator, four identical slotlines equally spaced along the ring and two differential-mode microstrip line to slotline transitions. By perpendicularly installing the slotline between the differential feeding line and the ring resonator, the coupling strength between them can be dramatically increased as desired. More importantly, only the differential modes can propagate along the slotline, so the proposed filter can naturally block the common modes (CMs) from propagation and achieve good CM suppression. To verify the design concept, a filter has been designed and fabricated. Good agreement between simulated and measured results is attained.

Balanced filters with wideband common mode suppression using dual-mode ring resonators

Two novel balanced filters with wideband common mode suppression using dual-mode ring resonators are proposed in this paper. Two and four transmission zeros close to the passband are realized to improve the selectivity for the differential mode. In addition, over 20-dB common mode suppression can be realized from 0 GHz to $5f_{0}$ ( $f_{0}$ is the center frequency of the passband), due to the all-stop transmission characteristic of the open/shorted coupled lines. To verify the presented concepts, two prototypes ( $\varepsilon_{r}=2.65$ , $h=1.0 {\rm mm}$ ) with 3-dB fractional bandwidths of 22.9% and 21.9% for the differential mode are designed and fabricated. The theoretical and measured results agree well and show good in-band filtering performance and high selectivity.

Bandpass Filter Loaded With Open Stubs Using Dual-mode Ring Resonator

A high selectivity bandpass filter loaded with open stubs using dual-mode ring resonator is presented in this letter. Sixth-order passband with six transmission zeros close to the passband is realized with two open stubs and open/shorted coupled lines. The transmission zeros near the passband can be adjusted conveniently by only changing the characteristic impedances of the coupled lines. For demonstration, a planar bandpass filter (3 dB bandwidth 20.6%) is designed and fabricated. Good filtering performance and high selectivity for the filter are realized and experimentally verified.

BANDPASS FILTER WITH FOUR TRANSMISSION ZEROS USING DUAL-MODE RING RESONATOR

A novel microstrip bandpass filter with four transmission zeros is proposed. Four transmission zeros close to the passband are realized to improve the selectivity for the passband. A sixth- order passband is realized with two shorted stubs and a dual-mode ring resonator. The transmission zeros near the passband can be adjusted conveniently by only changing the characteristic impedances of the coupled lines. For demonstration, a planar bandpass filter (3-dB bandwidth 21.9%) was designed and fabricated.

Dual-band dual-ring bandpass filter with large bandwidth ratio

A novel dual-band bandpass filter with large bandwidth ratio is proposed by using two dual-mode square ring resonators. By stretching the length of the loaded open stub of the inner ring, one of its first-order degenerate modes moves down and forms the first passband together with a pair of first-order degenerate modes of the outer ring resonator. Meanwhile, the second passband is constructed by another first-order degenerate mode of the inner ring resonator and its second-order degenerate mode. In this way, the realisable fractional bandwidth of the first passband can be largely enhanced with the new combination of multiple resonant modes. Finally, a prototype with a high fractional bandwidth ratio of two passbands has been realised and verified experimentally.

Dual-Mode Ring Resonator Bandpass Filter With Asymmetric Inductive Coupling and Its Miniaturization

Dual-mode ring resonator filters are implemented with asymmetric inductive perturbation for creating transmission zeros on both sides of the passband. In analysis, dependence of the resonance modes and the zeros on positions and sizes of both the inductive and capacitive perturbations is investigated. Under certain conditions, the even- and odd-mode frequencies for a capacitively perturbed ring are the same as the odd and even ones, respectively, for a ring with inductive perturbation. Theoretical background is clearly explained how the two transmission zeros are split up from the center frequency. Two dual-mode ring resonator filters are fabricated and measured for demonstration. To obtain a miniaturized circuit area, the 1-λ ring trace is folded into a double-ring or spiral configuration. The inductive perturbation is chosen as the crossover and implemented by a short high-impedance coplanar waveguide interconnection in the ground plane of the microstrip. Measurement results show good agreement with the simulation responses.

A Narrowband CMOS Ring Resonator Dual-Mode Active Bandpass Filter With Edge Periphery of 2% Free-Space Wavelength

This paper presents a monolithic transmission- line-based ring resonator dual-mode active bandpass filter (BPF) fabricated in a standard 0.13-μm complementary metal-oxide-semiconductor (CMOS) technology. The dual-mode ring resonator comprises a quasi-TEM complementary-conductive- strip transmission-line loop and a shunt metal-insulator-metal perturbation capacitor. Two CMOS cross-coupled pairs are integrated with the ring resonator symmetrically, forming a robust approach, which both enhances the quality factor of dual modes and reduces the resonator size significantly. Basic characteristics of the filter are discussed, including the unloaded resonant frequencies, transmission zeros, coupling coefficients, Q-enhancement mechanism, linearity, noise, and power consumption. The area of the proposed dual-mode active BPF is 270 × 270 μm2 (0.02 λ0 × 0.02 λ0) without dc-biasing circuits and pads. The measured results, in good agreement with the simulated data, demonstrate 0-dB insertion loss at the center operating frequency of 24.1-GHz, bandwidth of 640 MHz (2.32% fractional bandwidth), passband ripple of 0.556 dB, P1 dB of -25.43 dBm, IIP3 of -10.57 dBm, and noise figure of 14.7 dB under voltage supply of 1.8 V and current of 3.0 mA.

A NOVEL SINGLE AND DUAL-BAND MINIATURIZED MATCHED BAND-STOP FILTER USING STEPPED IMPEDANCE RESONATOR

In this paper in order to reduce the size and improve the performance of microwave filter, novel single and dual band matched band-stop filters are developed. A stepped impedance dual mode resonator is used, resulting in a much more compact size, than the conventional dual mode ring resonator that has an electrical length of 360◦. The proposed prototype is able to achieve high stop band attenuation even with low Q factor values. Moreover, for the short electrical length of this filter, the first spurious resonance occurs at 4.7 times the fundamental resonance frequency. Therefore, the proposed technique selectively removes only the fundamental resonance frequency when such a resonator is implemented. A theoretical analysis, along with an experimental prototype is proposed in order to demonstrate the feasibility of these proposed networks.

A Tunable Bandpass Filter with Switchable Bandwidth

A novel bandpass filter with tunable center frequency and switchable bandwidth is presented in this paper. This work is devoted to demonstrate a new approach to tune bandwidth of filters by changing the size of perturbation patch of dual-mode resonator. The proposed filter mainly consists of a dual-mode ring resonator, four varactor diodes and a pin diode. The center frequency could be conveniently tuned from 1.25 GHz to 1.45 GHz, and the fractional bandwidth can be tuned in two discrete states 8% and 12%, respectively. Comparison of the measured and simulated results shows good agreement about center frequency and bandwidth.

Ring-balun-bandpass filter with harmonic suppression

The Y-matrix of a three-port dual-mode ring resonator for a balun-bandpass filter (BPF) application is derived. Using Y parameters, it is verified that the structure theoretically satisfies the general balun conditions. The admittance slope parameters of the dual-mode ring resonator with one terminated port are derived so that one can design balun-BPFs using the conventional standard BPF design procedure. The proposed equations are validated by designing a balun-BPF. Inverters are then substituted with low-pass filter unit cells of λ/4 electrical length to suppress harmonics from the second to the fourth. The experimental measurements show good agreement with theoretical and electromagnetic-simulated predictions and suppressed harmonics below −30 dB up to fourth-order harmonics.

TRANSMISSION ZERO DESIGN GRAPH FOR DUAL-MODE DUAL-BAND FILTER WITH PERIODIC STEPPED-IMPEDANCE RING RESONATOR

Compact dual-mode dual-band bandpass fllters are realized with a single periodic stepped-impedance ring resonator. Neither extra resonator nor substrate layer is required for implementing the second passband. Based on the transmission line theory, a transmission zero design graph consisting of the transmission zeros together with the resonant frequencies of the resonator is developed against the space separation angle between the input and output ports. Based on this graph, when the line-to-ring feed structure is implemented, the space angle can be determined for the dual-mode dual-band design with designated zeros near the two passbands. It is believed that this is the flrst design graph for designating the transmission poles and zeros of a dual-mode ring resonator fllter before the excitation structure is realized. Three dual-mode dual-band bandpass fllters are carried out for demonstration. All circuits occupy only 60% of the area of the conventional ring resonator bandpass fllter

Design of a compact dual-mode ring resonator bandpass filter with harmonic suppression

An approach to suppress the harmonic responses in a dual-mode circular ring resonator bandpass filter is presented. Feed lines with one-sided coupling arms are suitably relocated around the ring resonator to introduce phase interference between two degenerate modes for simultaneously suppressing the second and third harmonics. Three open loop resonators at the rim of the ring are adopted to further suppress the second harmonic. By fabricating on a FR4 glass-epoxy base, this approach is demonstrated to have effectiveness in broadening the filter's rejection band in both simulations and measurements without affecting the fundamental response or increasing the device size.