Complementary Spiral Resonator Research Articles

Low‐loss compact diplexer based on complementary spiral resonators

AbstractThe article describes a novel low‐loss microwave diplexer based on compact planar filtering elements. These are composed of spiral resonators and etched directly onto the signal layer. Furthermore, their design and optimization prove to be easy, and their native high‐pass/low‐pass characteristics are perfectly suited for assembling a diplexer. To verify the claim, a diplexer is designed and fabricated. It operates at 1.9 GHz and 3.5 GHz, and it is intended for personal communications service and 5G applications. The proposed device has an active area of 15.5 mm 19.5 mm. It shows an insertion loss of 0.35 dB and 0.28 dB for the two channels, representing the lowest data reported in the literature for this kind of device and technology. Additionally, the −10 dB‐fractional bandwidths for the lower and upper bandwidths are 40.6% and 20.2%, respectively, and isolation is at least 25 dB for both channels.

Nondestructive Microwave Self-Oscillating Sensor Based on Complementary Spiral Resonator for Defect Evaluation of Metallic Mesh

Nondestructive Microwave Self-Oscillating Sensor Based on Complementary Spiral Resonator for Defect Evaluation of Metallic Mesh

A Millimeter Wave Triband Bandpass Filter Using Stub-Loaded Hexagonal Patch with Complementary Spiral Resonator

In this paper, a triband bandpass filter has been proposed for millimeter wave and 5G applications. The filter design is progressed using a complementary spiral resonator superimposed on a hexagonal patch measuring about 7 mm × 4.2 mm × 0.8 mm. employing Rogers 5880 as substrate with εr = 2.2. This triband filter is highly selective with sharp rejections emulating bandwidths of about 1.3 GHz, 2.5 GHz, and 1.8 GHz capable of supporting millimeter wave and 5G communications. The qualifying parameters of filter-like insertion loss have been realized between −0.6 dB and −0.16 dB and return loss between −19.12 dB and −28 dB for the corresponding three bands. Moreover, the performance attainment of the filter has been verified from the surface current distribution of the filter. The filter resonates at millimeter wave frequencies of 29.6 GHz, 32.5 GHz, and 35.8 GHz portraying a triband response. The simulated and measured results substantiated very well with each other.

Compact Multiservice Antenna for Sensing and Communication Using Reconfigurable Complementary Spiral Resonator

Compact Multiservice Antenna for Sensing and Communication Using Reconfigurable Complementary Spiral Resonator

High-Sensitivity Sensor Loaded With Coupled Complementary Spiral Resonators for Simultaneous Permittivity and Thickness Measurement of Solid Dielectric Sheet

High-precision measurement of permittivity and thickness enables advanced quality control of microwave substrates. In this article, a subwavelength planar microwave sensor is proposed, which is composed of a single-microstrip transmission line with a pair of coupled circular complementary spiral resonators (CSRs). Thus, two robust band-stop notches in the transmission response are developed, which can be utilized for simultaneous thickness and permittivity measurements of a dielectric sheet. The mutual capacitance and inductance, which quantify the coupling effect between the two resonators, are added to the equivalent lumped circuit model. They enhance the frequency shifts, thus improving sensitivity. The results of full-wave simulations and measurements on five different types of samples verify the concept’s effectiveness.

A metamaterial sensor for detecting the location of a sub-wavelength object

A metamaterial sensor is proposed to detect the random location of a sub-wavelength metallic object. The sensor is composed of a transmission line (TL), which supports the propagation of spoof surface plasmon polaritons (SSPPs) with localized electromagnetic (EM) field, and a complementary spiral resonator (CSR) that resonates strongly at designed frequencies around 0.9 and 2.7 GHz. Based on the shift of the resonance frequencies, this sensor is able to detect the location of a sub-wavelength metallic object (whose diameter is smaller than 0.6 mm) randomly attached to the CSR. A prototype of the sensor is fabricated and tested. In practice, the CSR is excited through the EM coupling of the SSPP TL, and the location of the metallic object is obtained through the transmission coefficient (S21). To improve the accuracy, a retrieval curve for locating is generated and calibrated. It is proved that the random location of the sub-wavelength object can be accurately detected inside an area of 9π mm2 with a low error of 2‰.

High-Sensitivity and Compact Time Domain Soil Moisture Sensor Using Dispersive Phase Shifter for Complex Permittivity Measurement

This article presents a time domain transmissometry soil moisture sensor (TDT-SMS) using a dispersive phase shifter (DPS), consisting of an interdigital capacitor that is loaded with a stacked four-turn complementary spiral resonator (S4-CSR). Soil moisture measurement technique of the proposed sensor is based on the complex permittivity sensing property of a DPS in time domain. Soil relative permittivity which varies with its moisture content is measured by burying the DPS under a soil mass and changing its phase difference while excited with a 114-MHz sine wave (single tone). DPS output phase and magnitude are compared with the reference signal and measured with a phase/loss detector. The proposed sensor exhibits accuracy better than ±1.2% at the highest volumetric water content (VWC = 30%) for sandy-type soil. Precise design guide is developed and simulations are performed to achieve a highly sensitive sensor. The measurement results validate the accuracy of theoretical analysis and design procedure. Owning the advantages of low profile, low power consumption, and high sensitivity makes the proposed TDT-SMS a good candidate for precision farming and internet of things (IoT) systems.

A Simple High-Resolution Near-Field Probe for Microwave Non-Destructive Test and Imaging

Non-destructive tests working at lower microwave frequencies have large advantages of dielectric material penetrability, lower equipment cost, and lower implementation complexity. However, the resolution will become worse as the work frequencies become lower. Relying on designing the structure of high field confinement, this study realizes a simple complementary spiral resonators (CSRs)-based near-field probe for microwave non-destructive testing (NDT) and imaging around 390 MHz (λ = 769 mm) whereby very high resolution (λ/308, 2.5 mm) is achieved. By applying an ingenious structure where a short microstrip is connected to a microstrip ring to feed the CSR, the probe, that is a single-port microwave planar circuit, does not need any extra matching circuits, which has more application potential in sensor arraying compared with other microwave probes. The variation of the electric field distribution with the standoff distance (SOD) between the material under test and the probe are analyzed to reveal the operation mechanisms behind the improved sensitivity and resolution of the proposed probe. Besides, the detection abilities of the tiny defects in metal and non-metal materials are demonstrated by the related experiments. The smallest detectable crack and via in the non-metal materials and the metal materials are of a λ/1538 (0.5 mm) width, a λ/513 (1.5 mm) diameter, a λ/3846 (0.2 mm) width and a λ/513 (1.5 mm) diameter, respectively. Moreover, to further evaluate the performance of the proposed probe, the defects under skin layer in the multilayer composite materials and the defects under corrosion in the carbon steel are inspected and imaged. Due to lower work frequency, high resolution, outstanding detection abilities of tiny defects, and large potentials in sensor arraying, the proposed probe would be a good candidate for microwave NDT and imaging.

A Flexible Microwave Sensor Based on Complementary Spiral Resonator for Material Dielectric Characterization

In this paper, a flexible microwave sensor for material dielectric characterization is presented. The sensor is composed of a two-turn complementary spiral resonator (CSR) in coplanar waveguide (CPW) technology developed on a flexible polyethylene terephthalate (PET) substrate. The sensing principle is based on the measured transmission coefficient of the designed structure, where the resonant frequency and its magnitude are in function of the dielectric properties of loaded materials under test (MUTs). A prototype of the proposed sensor is fabricated and experimentally validated by extracting the dielectric constant and loss tangent of the reference samples loaded above the region of the CSR. Specially, due to the flexibility, the fabricated sensor can be conformally attached to the palm of a dexterous robotic hand to function as robotic electronic skin for material dielectric characterization, more specifically, to obtain dielectric properties of the objects grasped by the dexterous robotic hand. Moreover, the sensing functionality of the sensor structure under different bending levels is validated by calculating the dielectric property of loaded objects with non-planar surfaces.

Low phase-noise oscillator based on SIW bandpass filter implementing at the Qsc-peak frequency

ABSTRACTIn this paper, a novel low phase-noise oscillator employing an substrate integrated waveguide (SIW) bandpass filter (BPF) embedded with a complementary spiral resonator (CSR) is proposed. The Qsc-peak frequency is chosen for the design of the oscillator to achieve optimal phase noise performance. The CSR exited by TM01 mode has been etched on the top metal of the circular cavity. Three transmission poles and three transmission zeros can be obtained by the proposed SIW BPF which is regarded as the frequency stabilization element. Meanwhile, a short summary about how to obtain a high Qsc-factor to achieve low phase noise performance has been illustrated. A C-band oscillator using a field effect transistor has been designed and experimentally demonstrated at 5.71 GHz with a 147.6 dBc/Hz phase noise at 1 MHz offset frequency. Moreover, the output power is −1.49 dBm with a figure of merit of −209.2 dBc/Hz and less than −32.8 dBm spurious harmonics is obtained.

Design and analysis of a super compact wide-band bandpass filter based on metamaterial resonators

In this paper, a novel compact wide-band bandpass filter (BPF) with a wide frequency range is presented. This filter consisting of a multi-mode resonator (MMR) and four metamaterial unit-cells benefits from a very compact size. Unit-cells based on a complementary spiral resonator (CSR) including a metallic via, improve both upper and lower stopband rejection and compensate the insertion loss (I.L) within the passband altogether. This wide-band filter presents a 3-dB bandwidth of 7.7 GHz, ranging from 3 GHz to 10.7 GHz and the Insertion loss is less than 0.7 dB over the passband. The measured results are in good agreement with both the full-wave electromagnetic simulation and the proposed circuit model results. The dimension of the fabricated filter is 0.128 λ × 0.1 λ (i.e., 5.6 × 4.4 mm2). This filter is considerably compact compared to the other wide-band bandpass filters with the same substrate.

Compact Microstrip Diplexer Based on CRLH Metamaterial Concept

ABSTRACTIn this paper, a compact microstrip diplexer based on resonant-type metamaterial transmission lines is proposed. The proposed diplexer is designed by cascading two bandpass filters with different center frequencies. The bandpass filter, which the proposed diplexer has been designed based on it, is realized by series of capacitive gaps with grounded stub on the upper metal layer and the complementary spiral resonators unit cell which etching on the ground plane. The proposed diplexer as a three-port device has been designed to operate at two arbitrary frequencies. The simulation results show that the three-port diplexer can separate two different frequencies effectively. In order to confirm the design procedure and the capability of the proposed diplexer in size reduction and selectivity, two prototype devices operative in the center frequencies at 2.4 and 3.5 GHz have been fabricated and tested. Good agreement between measurement and simulation results has been achieved. These one- and two-stage diplexers have the overall sizes of 0.19 λg × 0.05 λg and 0.34 λg × 0.06 λg, respectively. The proposed diplexers have many advantages in terms of compact size, low loss, high isolation, ease of fabrication, and high selectivity.

Harmonic suppression in short-circuited stub bandpass filter by means of a new miniaturized bandstop filter

In this article, a conventional short-circuited stub bandpass filter cascaded with a new miniaturized bandstop filter is presented which results in suppression of the spurious signals. The crown bandstop filter is proposed and designed using transmission line model. The combination of a crown bandstop filter, a complementary spiral resonator and a spurline is used to obtain the proposed bandstop filter with wide stopband and high rejection level. The proposed bandstop filter size is 0.31λg* 0.31λg and has a wide 3-dB stop bandwidth of 3.5 GHz. The prototype of the harmonic suppressed short-circuited stub bandpass filter is fabricated and measured. The measured upper stopband is better than 30 dB up to 3.5f0. The measured results are in good agreement with corresponding simulation results.

Composite right/left‐handed based compact and high gain leaky‐wave antenna using complementary spiral resonator on HMSIW for Ku band applications

In this communication, a novel compact high gain composite right/left-handed (CRLH) based leaky-wave antenna (LWA) is presented at Ku band. A half-mode substrate-integrated waveguide incorporated with a suitably oriented complementary quad spiral resonator (CQSR) is used to achieve a CRLH LWA. The unit cell is realised by a CQSR in such a way that the orientation of spirals exhibits higher leakage loss having a minimum cross coupling between them. The antenna is capable of scanning backward to forward along with a broadside direction in visible space. The proposed configuration has a length of 4.85 λ 0 which can scan within the frequency range of 13.5-17.8 GHz having a beam scanning range of 86° (-66° to 20°) and a maximum gain of 16 dBi. The simulated reflection coefficient of the proposed antenna is below -10 dB throughout the working frequency range with a side-lobe level of below -10 dB. The designed prototype is more compact in nature having high gain, fair scanning range, and good cross-polarisation level along with simpler design methodology and tuning capability to enhance the gain as well as radiation efficiency maintaining a fixed size. The proposed antenna could be a promising candidate in Ku-band applications like fixed satellite services, and broadcast satellite services etc.

A compact dual-band 2 × 1 metamaterial inspired mimo antenna system with high port isolation for LTE and WiMax applications

This article proposes a compact (43 × 26 × 0.8 mm3) dual-band two-element metamaterial-inspired MIMO antenna system with high port isolation for LTE and WiMAX applications. In this structure, each antenna element consists of a square–ring slot radiator encircling a complementary split ring resonator. A tapered impedance transformer line feeds these radiating apertures and shows good impedance matching. A 2 × 3 array of two-turn Complementary Spiral Resonator structure between the two antenna elements provides high dual-band isolation between them. The fabricated prototype system shows two bands 2.34 – 2.47 GHz (suitable for LTE 2300) and 3.35 – 3.64 GHz (suitable for WiMAX). For spacing between two antennas of 10 mm only, the measured isolation between the two antenna elements in the lower band is around −32 dB while that in the upper band is nearly 18 dB. The system shows a doughnut-shaped radiation patterns. The peak measured antenna gains for the proposed MIMO system in the lower and higher bands are 3.9 and 4.2 dBi, respectively. The MIMO system figure of merits such as the envelope correlation coefficient, total efficiency are also calculated and shown to provide good diversity performance.

MULTI-BAND ANTENNA ARRAY BASED ON DOUBLE NEGATIVE METAMATERIAL FOR MULTI AUTOMOTIVE APPLICATIONS

This paper presents a design of multi-band array antenna based on Double Negative Metamaterial (DNM) unit cells for multi-automotive applications. The antenna consists of 4 × 4 rectangular and circular radiating patches connected in series using microstrip lines and fed by a 50Ω corporate microstrip line. An array of 4×6 wire loaded complementary spiral resonator (CSR) unit cells is placed on its reverse side to provide miniaturization and multiband features to the proposed design. The reflection coefficient (S11), mutual coupling, effective diversity gain (EDG), envelope correlation coefficient (ECC), and radiation patterns are evaluated for four elements of the proposed antenna placed in four different locations on the car body model. Simulations and measurements indicated that the proposed antenna features a low mutual coupling ( 9.995), high efficiency (72%-95%), and low on-car detuning over the desired five bands; 1.99GHz to 3.03 GHz, 5.15 GHz to 6.369 GHz, 7.67 GHz to 7.99GHz, 9.91GHz to 10.23 GHz, and 11.79 GHz to 12.2GHz. The performance of ECC between four antennas on car body has been investigated in different cases of isotropic, indoor, and outdoor. The metallic effect on antennas performance also has been investigated by evaluating the mutual coupling and transmission coefficient between two antennas served as transmitter and receiver with presence of car body. The results show transmission coefficient of proposed DNM antenna with metallic presence almost identical to free space across desired frequency bands. With all capabilities mentioned the antenna has potential for WiFi/WiMAX, Vehicleto-Vehicle (V2V), transportable earth exploration satellite, military requirement for land vehicles, and earth stations on vessels applications.

Compact dual-band SIW filter with CSRRS and complementary spiral resonators

A novel structure for dual-band substrate integrated waveguide filters is presented in this article. To obtain advantages of compact structure and good performance, complementary split-ring resonators (CSRRs) are simplified, and loaded into the waveguide surface with complementary spiral resonators (CSRs) together. As a result, two passbands below the cutoff frequency of the waveguide are obtained. Every passband has two transmission zeros and two transmission poles. This article points out that the combination of CSRRs and CSRs cannot only make the structure more compact, but also produce a positive interaction between the resonators, providing a new direction for the application of those two right/left-hand structures. To verify the presented concept, the filter is fabricated. The measured results are in good agreement with the simulation. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1–4, 2016

Compact Microstrip Antenna With Enhanced Bandwidth by Loading Magneto-Electro-Dielectric Planar Waveguided Metamaterials

A new concept of planar magneto-electro-dielectric waveguided metamaterials (MED-WG-MTM) is proposed to manipulate the effective permeability μ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> and the effective permittivity ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> . The MEDWG-MTM cell consists of an electric complementary spiral ring resonator (CSR) in the upper metallic plane and a magnetic embedded Hilbert-line (EHL) in the ground plane. The characterizations and working mechanisms are investigated in depth through eletromagnetic (EM) simulation, circuit model calculation and effective material parameters analysis. Numerical results show that the MED-WG-MTM can be manipulated with a larger refractive index for miniaturization and a larger wave impedance for bandwidth (BW) enhancement. For demonstration and potential applications, a microstrip patch antenna working at 3.5 GHz and occupying an area of only 0.20λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.20λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is designed by using the derived flexible three-step frequency tuning method. A good agreement of results between the simulations and measurements suggests that the designed antenna advances in many aspects such as compact dimensions with a 42.53% miniaturization, broad operation band with a 207% impedance BW enhancement, and comparable radiation performances relative to its conventional counterparts.

Two-dimensional fractal metasurface and its application to low profile circularly polarized antennas

Two-dimensional (2D) Wunderlich-shaped fractal reactive impedance surface (WRIS) is designed and extensively investigated to reduce the dielectric substrate thickness without deteriorating the electromagnetic characteristic. Slot resonators, Hilbert-shaped complementary single ring resonator (HCSRR), and the complementary three-turns spiral resonator have been used to achieve antenna miniaturization and also to render the circularly polarized (CP) wave. For demonstration, WRIS-inspired HCSRR- and TCSR-loaded CP antennas are optimized, fabricated, and measured. Numerical and experimental results indicate that both antennas owe compact size smaller than 0.18λ0 × 0.25λ0 × 0.017λ0, exhibit comparable impedance, and axial ratio (AR) bandwidth better than 1.60% and pure CP performances. Furthermore, the antennas are free of metallic via holes and easy of fabrication, indicating promising applications in wireless communication systems.

Multi-band Monopole Antennas Loaded with Metamaterial TL

AbstractA novel metamaterial transmission line (TL) by loading complementary single Archimedean spiral resonator pair (CSASRP) is investigated and used to design a set of multi-frequency monopole antennas. The particularity is that the CSASRP which features dual-shunt branches in the equivalent circuit model is directly etched in the signal strip. By smartly controlling the element parameters, three antennas are designed and one of them covering UMTS and Bluetooth bands is fabricated and measured. The antenna exhibits impedance matching better than –10 dB and normal monopolar radiation patterns at working bands of 1.9–2.22 and 2.38–2.5 GHz. Moreover, the loaded element also contributes to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. The proposed antenna is also more compact over previous designs.