Conventional Complementary Split Ring Resonator Research Articles

Ultra-compact half-mode substrate integrated waveguide bandpass filters with IRCSRR metamaterial on reinforced hydrocarbon polymer ceramic composites

In this work, metamaterial-enabled ultra-compact evanescent-mode half-mode substrate integrated waveguide (HMSIW) bandpass filters are developed by loading inner-rotary complementary split-ring resonator (IRCSRR) on reinforced hydrocarbon polymer ceramic composites substrate. In the proposed IRCSRR, inner-rotary slots are etched inside the conventional complementary split-ring resonator (CSRR) metamaterials to enhance the product of equivalent inductance and capacitance without occupying extra circuit area. Therefore, the proposed HMSIW-IRCSRR filters can obtain more size reduction with the same operation frequency as compared with the conventional CSRR-based ones. Similar as the conventional CSRR case, the evanescent-mode transmission below the dominant cutoff frequency of HMSIW can be produced by the negative permittivity effect of IRCSRR, and a transmission zero (TZ) at the upper stopband can be simultaneously generated by the mutual coupling between HMSIW and IRCSRR. Then, to improve the upper stopband performance, source-load coupling topology is utilized in the two-pole filters, which can produce multiple extra TZs. Meanwhile, multiple microstrip L/T-shaped open stubs are employed to introduce hybrid low-pass effect to further extend the upper stopband much wider. To demonstrate the availability of the aforementioned concepts, a series of HSMIW-IRCSRR filters are experimentally designed, fabricated and verified. Measured results shows that both ultra-compact sizes and excellent frequency-selecting performance are achieved simultaneously, as well as good agreement with simulations, all of which illustrating quite good promises for the practical radio frequency and microwave applications.

Equal/unequal half mode substrate integrated waveguide filtering power dividers using an ultra-compact metamaterial unit-cell

Abstract In this paper, a novel ultra-compact metamaterial unit-cell is introduced. The proposed unit-cell consists of one modified rings which has been designed based on the fractal technique and meander technique. These techniques are used to reduce the physical size of the conventional complementary split ring resonators (CSRRs). In the proposed metamaterial unit-cell which is called the fractal/meander CSRR (FMCSRR), the slot lines in the conventional CSRRs are replaced by the fractal and meander slots, simultaneously. The FMCSRR unit-cell is a planar metamaterial element which exhibits negative permittivity and is considered as electric dipole when excited by an axial electric field. Thus, the FMCSRR unit-cell is modeled as a shunt resonator tank. Therefore, by using the proposed FMCSRR configuration, all of the interior space of the ring has been used and the slot lines have been increased. Consequently, the higher inductance has been achieved and the resonance frequency of the proposed FMCSRR unit-cell becomes lower compared with the conventional CSRR. That’s mean the electrical size of the introduced unit-cell FMCSRR unit-cell is smaller than the conventional CSRR with the same physical sizes. A microstrip notch band filter, a microstrip band-pass filter, a half mode substrate integrated waveguide (HMSIW) band-pass filter and three HMSIW filtering power dividers (FPDs) with different power division ratios of 1:1, 1:4, and 1:8 have been designed to illustrate the ability of the proposed FMCSRR unit-cell in the size reduction. All of the designed devices operated at 2.4 GHz which are suitable for WLAN applications. For verification the performance of the utilized techniques in miniaturization of the dimension, the designed equal/unequal HMSIW FPDs have been fabricated and tested. A reasonable agreement between simulated and measured results has been achieved. The results confirmation that a miniaturization about 79% has been obtained. The total size of the proposed HMSIW FPDs are about 0.09λ g × 0.09λ g. The proposed HMSIW FPDs have many advantages in terms of compact size, low insertion loss, high selectivity, easy integration with the other planar circuits, and controllable bandwidth.

Dielectric loading method for doubly resonant enhancement of third-harmonic generation from complementary split-ring resonators

Nonlinear optical response could be greatly enhanced when metasurfaces support plasmonic resonances at both fundamental and harmonic wavelengths. However, it is still challenging to fulfill the doubly resonant condition. Here, we propose a dielectric-loading method, which simply coats a conformal thin dielectric layer onto the plasmonic metasurfaces, to introduce an additional degree of freedom and make the doubly resonant condition easily fulfilled. We demonstrate that by simultaneously tuning the thickness of the coated dielectric layer and the geometrical parameters of the gold complementary split-ring resonators (CSRRs), the doubly resonant enhancement of third harmonic generation (THG) could be achieved for any given fundamental wavelengths. We also experimentally verify this concept and show that the THG intensity in the dielectric-loaded CSRRs under the doubly resonant condition could be further increased about 3 times as compared with the case of the conventional CSRRs.

A novel dual-band bandpass SIW filter loaded with modified dual-CSRRs and Z-shaped slot

In this paper, a novel dual-band bandpass substrate integrated waveguide (SIW) filter has been presented by loading two modified dual complementary split ring resonators (CSRRs) and a Z-shaped slot on the top side of SIW. The modified dual-CSRR structure is obtained by folding its outer ring, adding T-shaped branch to its inner ring and placing the splits of the inner and outer rings of CSRR in the same direction. The modified structure allows the electromagnetic wave to propagate in the passband below the cutoff frequency of the waveguide. Compared with conventional CSRR of the same size, it has two passbands and work at a lower frequency. A dual-band bandpass filter is proposed by placing two proposed dual-CRSSs face-to-face on the top side of SIW. In order to improve the performance of the filter, the Z-shaped slot is introduced to enhance the electromagnetic coupling, thus increasing the transmission zero point, broadening the passband and enhancing the flatness in the band, and realizing the center frequency shift of the passband to the left. To validate the design and analysis, a dual-band bandpass SIW filter loaded with two modified dual-CSRRs and a Z-shaped slot is manufactured and measured. The first pass band of the filter has a center frequency of 1.94 GHz, a 3 dB band width of 0.28 GHz, the second pass band has a center frequency of 4.85 GHz and a 3 dB band width of 0.13 GHz, which is basically consistent with the simulation results.

Design of ZnO/N-Doped Graphene Nanohybrid Incorporated RF Complementary Split Ring Resonator Sensor for Ammonia Gas Detection

The integration of nanomaterials with the micro-wave technology is a significant step toward the development of low-cost and low-power RF gas sensors. But, the issues associated with materials like insignificant surface area and poor conductivity, are barriers for the rapid detection of wide range of gas concentrations. In this paper, we demonstrate the proof-of concept using an RF complementary split ring resonator (CSRR) integrated ZnO/N-doped graphene (NGN) nano-hybrid to study the gas sensing properties. This RF device senses the presence of ammonia based on the change in the electrical conductivity of the nanohybrid material upon gas exposure. For this, we have designed and fabricated various new CSRR structures, namely, the meander (M-CSRR) and the CSRR, with the concentric-etched square pattern (SP-CSRR) other than the conventional CSRR (C-CSRR). The fabricated CSRRs are coated with the solvothermal methodically prepared ZnO/NGN nanomaterials and a comparison among them is also made. The comparison revealed that the SP-CSRR coated ZnO/NGN sensor had the maximum shift in the S21 resonance frequency ( $\Delta \text {f}_{\mathbf {S21}} = 13$ MHz at 100 ppm) among all at room temperature. Furthermore, the SP-CSRR-ZnO/NGN sensor exhibited a large-S21 frequency shift of 133 MHz for 500 ppm of ammonia and has shown excellent reproducibility with 0.05% of variation. We have also projected the plausible sensing mechanism for this RF sensing device.

Miniaturized half-mode substrate integrated waveguide diplexer based on SIR–CSRR unit-cell

A miniaturized diplexer based on half-mode substrate integrated waveguide (HMSIW) technology by loading a novel metamaterial unit-cell is proposed. The stepped-impedance resonator (SIR) technique has been used in order to miniaturize the physical size of the conventional complementary split ring resonators (CSRRs). The proposed metamaterial unit-cell, which is called SIR–CSRR, consists of two modified rings which the stepped-impedance slot lines are utilized instead of the conventional slot lines in the CSRRs. The proposed diplexer has been designed by cascading two bandpass filters with different center frequencies. The HMSIW bandpass filters are implemented by etching two SIR–CSRR unit-cells with different sizes. The design procedure is based on the theory of evanescent mode propagation which the SIR–CSRR unit-cells behave as an electric dipoles. A forward-wave passband below the intrinsic cutoff frequency of the HMSIW structure has been achieved by loading the SIR–CSRR unit-cells on the metal surface of the HMSIW structure. This proposed diplexer represent high selectivity and compact size by using of the sub-wavelength resonators. The designed diplexer has been fabricated and experimental verification have been provided. The measured results are in a good agreement with the simulated ones. The total size of the proposed diplexer is about 0.27λg × 0.11λg. The proposed diplexer show significant advantages in terms of size reduction, low loss, high selectivity, high Q-factor, easy bandpass frequency shifting, easy fabrication and, easy integration with other planar microwave circuits.

Analysis and design of a compact CRLH inspired – Defected ground resonators for triple band antenna applications

In this work, a triple-band negative refraction index metamaterial antenna employing a new configuration of the complementary split ring resonator is presented. The antenna has been designed to operate at 2.4 GHz, 2.9 GHz, and 4.38 GHz. The complementary split ring resonator is etched in the ground plane of a microstrip patch with a new shape of defected ground structure for reducing the particle size. The configuration has the advantages of smaller size compared to conventional complementary split ring resonators presented in the literature. The proposed antenna has a patch size of 28 × 28 mm2. Compared to conventional single band microstrip patch radiator size; its size has been reduced by 30% at the lowest operating frequency. The antenna has reflection coefficient less than −10 dB at the three operating frequencies. The antenna has a reasonable gain at the three operating frequencies of 3.28 dB, −4.5 dB and −3.1 dB at 2.4 GHz, 2.9 GHz, and 4.38 GHz, respectively. Also, the antenna efficiency is 57.6%, 6.3%, and 12.3% at these frequencies, respectively.

A novel super compact half‐mode substrate‐integrated waveguide filter using modified complementary split‐ring resonator

A novel super compact filter based on half-mode substrate-integrated waveguide (HMSIW) technology loaded by the modified complementary split-ring resonator (MCSRR) is proposed. The working principle of the proposed filter is based on the evanescent-mode propagation technique. According to this technique, by loading the complementary split-ring resonator (CSRR) on the metal surface of the substrate-integrated waveguide (SIW) structure, an additional passband below the SIW cutoff frequency can be obtained. In order to miniaturize the physical size of the conventional CSRR, a new method is introduced. In the proposed MCSRR unit-cell, the meander slots are carved inside all of the interior space of the ring. Accordingly, the length of the slot is increased which leads to an increase in the inductor and capacitor of the proposed structure without occupying the extra space. Therefore, the electrical size of the proposed MCSRR unit-cell is reduced. Consequently, the resonance frequency of the proposed MCSRR unit-cell is decreased compared to the conventional CSRR with the same sizes. Namely, the lower resonance frequencies can be achieved by using this technique without increasing the size of the unit-cell. In order to confirm the miniaturization technique, two HMSIW filters loaded by the proposed MCSRR unit-cell are designed, fabricated, and experimental verifications are provided. The results show that a miniaturization about 67% is achieved.

Compact metamaterial unit-cell based on stepped-impedance resonator technique and its application to miniaturize substrate integrated waveguide filter and diplexer

In this article, a new miniaturized metamaterial unit-cell using stepped-impedance resonator technique is proposed. The proposed unit-cell is used to miniaturize the physical size of the conventional complementary split-ring resonators (CSRRs). In the proposed unit-cell which is called complementary G-shaped resonator (CGR), the slot line in the conventional circular CSRR is replaced with the stepped-impedance slot line. As well as, by carving two trapezoidal shapes inside the inner ring, the resonance frequency of the proposed CGR unit-cell has been more decreased. Compared to the conventional circular CSRR structure, the electrical size of the proposed CGR is decreased and miniaturization is occurred. To investigate the performance of the proposed CGR unit-cell in the size reduction, two substrate integrated waveguide filters and a diplexer are designed. To validate the proposed miniaturization technique, the designed filters and diplexer loaded by the CGR unit-cell are fabricated and measured. The measured results are in a good agreement with the simulated ones. The results shows that, a miniaturization factor about 0.69 is achieved.

Miniaturization of substrate integrated waveguide filters using novel compact metamaterial unit-cells based on SIR technique

In this paper, three novel compact metamaterial unit-cells are proposed. The proposed unit-cells are based on the concept of the stepped-impedance resonator (SIR) technique which are used to miniaturize the physical size of the conventional complementary split ring resonators (CSRRs). The proposed metamaterial unit-cells consists of two modified rings so that in these unit-cells, the slot lines in the conventional CSRRs are replaced by the stepped-impedance slot lines. The electrical size of the proposed unit-cells called the SIR-CSRR are larger than the conventional CSRR. To investigate the performance of the proposed SIR-CSRR unit-cells in the size reduction, three substrate integrated waveguide filters loaded by SIR-CSRR unit-cells with different configurations are designed. By loading the SIR-CSRRs on the surface of the waveguide, an additional forward-wave passband propagating below the initial cut-off frequency of the waveguide is produced. Consequently, by using the proposed SIR-CSRR unit-cells instead of the conventional CSRRs, miniaturization with arbitrary ratio are achieved. In order to validate the proposed miniaturization technique, the designed filters are fabricated and measurement results are provided. Good agreement between simulation and measurement results are achieved.

Stopband Performance Improvement of CSRR-Loaded Waveguide Bandpass Filters Using Asymmetric Slot Structures

This letter presents a simple waveguide filter structure having planar structure that can control transmission zeros (TZs) and center frequency independently. The planar structure is composed of the conventional complementary split-ring resonator (CSRR) and asymmetric slot structures. The planar structures resonate at particular frequencies and introduce total 2N TZs, above and below the passband of an Nth-order filter, and thus also improve the stopband performance of a planar CSRR-based waveguide bandpass filter. To demonstrate it, a third-order CSRR-loaded bandpass filter has been considered and analyzed. It has been shown that by varying the length of the asymmetric slot structures the TZs can be independently controlled.

Half‐mode substrate integrated waveguide bandpass filter loaded with horizontal–asymmetrical stepped‐impedance complementary split‐ring resonators

A half-mode substrate integrated waveguide (HMSIW) bandpass filter loaded with modified complementary split-ring resonators (CSRRs) is presented. The modified CSRR, realised by utilising horizontal–asymmetrical stepped-impedance (SI) structure in the conventional CSRR, can enhance the equivalent capacitance and inductance of the CSRR and consequently shift the resonant frequency downwards. Therefore, for the same operation frequency, the SICSRR can occupy smaller size than the conventional CSRR, which provides a promising method to achieve size-reduction in microwave circuits. To verify the effectiveness of miniaturisation introduced from the proposed HMSIW-SICSRR resonator, a two-pole bandpass filter is implemented. Moreover, the measured results are in good agreement with the simulated ones.

Composite right/left handed transmission line based on open slot split ring resonator

AbstractIn this article, an open slot split ring resonator (OSSRR) is introduced to realize a composite right/left handed (CRLH) transmission line structure in microstrip technology.The CRLH line is synthesized by etching OSSRR in the ground plane and interdigital capacitor in the microstrip line. Simulated and measured scattering parameter of the structure is presented. The dispersion characteristic of proposed structure is also shown. The proposed structure is 15% smaller than the conventional complementary split ring resonator structure. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1729–1731, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25330

Notched UWB bandpass filter using complementary single split ring resonator

In this paper, a simple method to obtain a notch in the ultra-wideband (UWB) bandpass filter is presented. UWB bandpass filter is designed using ground plane aperture technique. To reject the undesired wireless local area network (WLAN) signals, a complementary single split ring resonator (CSSRR) is placed under the coupled lines of the bandpass filter. The CSSRR has flat insertion loss and good roll off rate than the conventional complementary split ring resonator (CSRR). The proposed filter offers an ultra wide bandwidth bandpass filter characteristics with a steep notch function around 5.5GHz. Hence the interference from the devices operated in the IEEE 802.11a spectrum can be avoided properly. IE3D simulation results of the notched UWB bandpass filter is in good agreement with the measurement results.

COMPLEMENTARY SPLIT RING RESONATORS OF LARGE STOP BANDWIDTH

Novel complementary split ring resonator (CSRR) is introduced to increase the stop bandwidth. Despite of their exotic behavior due to negative permittivity, their performance is limited by their stop bandwidth. The orientation of CSRR etched on the ground has strong coupling that can be altered for the increased stop bandwidth. The proposed design has measured stop band from 4∼ 7.25GHz whereas conventional CSRR of same dimension has stop band from 4.1∼ 5.0GHz.