Asymmetric Coplanar Waveguide Research Articles

CRLH‐TL‐loaded metamaterial antenna with frequency band and polarization reconfigurability

SummaryIn this communication, an asymmetric co‐planar waveguide (ACPW)–fed composite right–left‐handed transmission line (CRLH‐TL)–based frequency band and polarization reconfigurable antenna (RA) is presented. The reconfigurability is achieved by using a PIN diode. When the diode is in OFF state, meander line works as part of ground. Hence, the antenna is like a circular patch antenna working at 5.15 GHz. In the ON state, the antenna works as a CRLH‐TL‐based antenna with an additional lower band resonating at 2.45 GHz. The antenna also has circular polarization (CP) property. The lower 2.4 GHz band is covering for IEEE 802.11 b/g/n/ax/be applications, whereas the higher band is covering the WiFi bands of IEEE 802.11a/h/n/ac/ax/be applications with CP radiation (upper band). This antenna is effective in a scattering environment such as in urban areas and indoor communication.

A monopole broadband circularly polarized antenna with coupled disc and folded microstrip stub lines

A broadband circularly polarized (CP) printed monopole antenna which fed by coplanar waveguide (CPW) is proposed in the paper. The structure of the novel antenna includes a quarter circular disc radiating monopole, a coupled circular patch, and a bent L-shaped microstrip stub line. The L-shaped microstrip stub line is used to widen the impedance bandwidth and generate a horizontal component of the electromagnetic wave. The adoption of the asymmetric ground coplanar waveguide structure with the single-feed technology and the coupled circular patch, simultaneously achieve wide impedance bandwidth and wide axial ratio (AR) bandwidth. The structure parameters and the surface current of the designed antenna are analysed. The simulation and the measurement are conducted, showing good characterizations of the designed antenna. The 10-dB impedance bandwidth is 7.57 GHz, the fractional bandwidth from 6.05 to 13.62 GHz is 76.9%, the 3-dB axial ratio bandwidth is 3.01 GHz, and the fractional bandwidth from 6.05 to 9.06 GHz is 39.8%. The antenna can generate right/left hand circularly polarized waves in the direction of ± z axis. The designed antenna has wide applications in the fields of Internet of Things (IoT), broadband dual-CP communication systems and polarization diversity systems, wireless personal area network and other advanced communication systems.

DESIGN OF DUAL BAND ASYMMETRIC CPW-FED D SHAPED PATCH ANTENNA FOR RADAR APPLICATIONS

ABSTRACT-In this paper a D shaped substrate conformal patch antenna by coplanar waveguide(CPW)-FED is proposed for Radar applications. As it is a asymmetrical CPW fed antenna the design consists of D-shaped patch and ground plane of different lengths separated by a feedline on the same side of substrate .The antenna is designed with the material FR4_Epoxy substrate with dielectric constant 4.4 and thickness 1.59mm. As per the simulation results, the proposed antenna can resonate at frequencies 7.77GHz and 12.6GHz which are used for satellite communications. This antenna is simulated using HFSS (High Frequency Structure Simulation)software and the basic parameters of antenna such as return loss, radiation pattern, bandwidth are analysed. Keywords-CPW-Fed, Antenna, Radar, polarization, impedance.

High-Gain and Wideband Planar Endfire Antenna Implemented via Spoof Surface Plasmon Polaritons and Dielectric Lens for X-Band Applications

This letter proposes a wideband, high-gain, and planar endfire antenna using odd-mode spoof surface plasmon polaritons (SSPPs) and dielectric lens. The SSPPs of the odd mode are excited via a novel asymmetric coplanar waveguide feeding configuration, consisting of a row of gradient slots etched inside of one ground plane. Symmetric SSPPs structure serves as a radiator element to realize stable endfire radiation. By extending a planar elliptical dielectric lens at the end of the substrate, the gain and front-to-back ratio (FBR) of the proposed antenna are further enhanced. The proposed endfire antenna is fabricated and measured to certify the design concept. Measured results indicate the endfire antenna obtains a desired operating band of 7.9–13 GHz, a high peak endfire gain of 14.8 dBi, and an average efficiency of 80%. Moreover, the FBR is better than 20 dB over the wide bandwidth with an optimal peak FBR up to 40 dB.

Waveguide-coupled heterodyne terahertz detector based on AlGaN/GaN high-electron-mobility transistor

We report a room-temperature, low output impedance, broad intermediate-frequency (IF) bandwidth field-effect terahertz detector based on an AlGaN/GaN high-electron-mobility transistor (HEMT) integrated in a metal waveguide. The waveguide detector equips a pair of quasi-Yagi antenna probes that are used to couple the terahertz energy to the HEMT channel. The gate is configured as an asymmetric edge-coupled coplanar waveguide transmission line. This terahertz electric field is asymmetrically distributed in the channel along the edges of the transmission lines. The responsivity and noise for direct and heterodyne detections are characterized and analyzed at different local oscillator (LO) powers. The noise-equivalent power in direct detection is below 189 pW/Hz1/2. Operated in a heterodyne mode with a LO power of −3 dBm, the detector offers a conversion loss less than 55 dB in a frequency band of 320–340 GHz. The channel in a form of transmission line performs the broad IF bandwidth, which is increased to gigahertz range (3 GHz), and reduces the output impedance to 377 Ω which is about 20 times lower than previously reported. The transmission-line impedance could be optimized together with the distribution of the terahertz electric field in the gated channel to reduce the conversion loss.

A Miniaturized Wideband Planar Bow-Tie Slot Antenna with Asymmetric CPW

In this paper, a novel miniaturized wideband planar bow-tie slot antenna is proposed. For the purpose of miniaturization and wide bandwidth, the effects of the dimension and shape of the bow-tie slot and feed structure are analyzed. This antenna adopts a water droplet slot, fed by an optimized asymmetric coplanar waveguide (CPW). By adjusting the feeding line, the impedance characteristic of the antenna is greatly improved that leads to a broader bandwidth. The proposed antenna operates from 2.8 GHz to 5.25 GHz with a gain of 3.8 dB. Compared with the traditional triangle bow-tie antenna, the relative bandwidth of the proposed antenna is broadened to more than 61%, while the size is reduced by about 36%, which indicates the proposed antenna is suitable for a variety of wireless applications.

Asymmetric CPW-fed hexagonal monopole antenna with Boomerang-shaped Fractals for ultra-wideband applications

Abstract In recent days, miniaturized antennas have gained significance in portable ultra-wideband (UWB) applications owing to its broad coverage spectrum. Fractal antennas have become popular in this context owing to the three properties: self-similarity, space-filling, and lacunarity, thereby producing miniaturization with a broad spectrum. Conventional Fractal antennas achieve a good impedance bandwidth, relatively high gain, at the cost of trade-off between compact size, radiation characteristics and broad spectrum. In this paper, an asymmetric coplanar waveguide–fed hexagonal monopole antenna with Boomerang-shaped Fractals is proposed for UWB characteristics with relatively high antenna gain and wide bandwidth. The miniaturization of the antenna is realized by the Fractal structure. The size of the antenna is to be 0.287 λ r × 0.287 λ r × 0.009 λ r, where λ r is the resonating wavelength at 3.45 GHz. The proposed antenna is printed on a 0.8-mm-thick FR-4 substrate with relative dielectric constant of 4.4 and a loss tangent of 0.02. From frequency-domain analysis, the experimental results reveal that the fractional bandwidth is 101.7% and the peak antenna gain detected is 5.1 dBi. The radiation performance of the antenna was nearly omnidirectional. From the time-domain analysis, group delay and three different Fidelity Factors i.e. Fidelity Factor (FF), System Fidelity Factor (SFF), and Fidelity Factor of System (FFS), the proposed antenna is found to have negligible distortion. As the bandwidth meets up to fractional bandwidth above 20% and absolute bandwidth greater than 500 MHz, the proposed antenna is suitable for 3.45–10.6 GHz UWB applications.

Wideband asymmetric coplanar waveguide antenna using composite right/left‐handed transmission line

AbstractA broadband asymmetric coplanar waveguide antenna is designed. In this design, two periodical composite right/left‐handed transmission line (CRLH‐TL) unit cells were chosen to generate three resonating modes. The broadband characteristic of this antenna can be achieved by combining the first‐negative‐order resonance, zeroth‐order resonance, and first‐positive‐order resonance of CRLH‐TL. A prototype structure of our proposed antenna has been fabricated and tested. The dimensions of the antenna are 30.0 × 40.0 × 1.6 mm3, which corresponds to 0.19 × 0.25 × 0.01 , where is the free‐space wavelength at 1.88 GHz. The measured band in which S11 is below −10 dB ranges from 1.80 to 3.75 GHz with the fractional bandwidth of 70.27%. The radiation patterns of the proposed antenna are highly consistent throughout the operating band, which covers the band of WiMAX, with the measured average peak gain of 2.77 dBi and radiation efficiency of 86.63%.

An Asymmetric Meandered Line Based Dual-Band ENG-TL Antenna Loaded with Complementary Closed Ring Resonators for Gain Enhancement

In this article, an asymmetric coplanar waveguide (CPW)-fed dual-band ENG-TL antenna with gain enhancement using complementary closed ring resonators (CCRRs) has been designed and validated. The proposed antenna consists of an asymmetric rectangular patch, meandered line inductor, coplanar ground planes, square-shaped CCRRs, and a radial stub. Simulated results show that the proposed antenna offer triple-band characteristics at 1.28 GHz (1.26–1.29 GHz), 2.61 GHz (2.57–2.65 GHz), and 4.3 GHz (4.15–4.49 GHz). However, the third band has been found as weak resonance and consequently not shown in the paper. Measured results show that the proposed antenna exhibits proper dual-band characteristics covering frequencies 1.18–1.29 GHz (centered at 1.24 GHz) and 2.40–2.68 GHz (centered at 2.56 GHz). Considering fZOR = 1.24 GHz, presented antenna has an electrical size of 0.103 λ 0 × 0.093 λ 0 × 0.0066 λ 0. The proposed antenna has a simulated gain of 1.5 and 2.01 dB at 1.28 and 2.61 GHz, respectively, in the direction of maximum radiation. Above reflection and far-field characteristics makes this antenna suitable for aeronautical radio-navigation (960–1215 MHz), space to earth radio-navigational satellite (1215–1240 MHz) communications. Moreover, the antenna can be potentially built-in smartphones for LTE (2.5–2.69 GHz), WLAN (2.4–2.484 GHz), and WiMAX (2.5–2.69 GHz) applications where gain requirement is reasonable.

Multiband isolator based on a coplanar metaline

This study presents for the first time the feasibility of a coplanar isolator using YIG material for applications in the Ku, K and Ka bands. The proposed structure is an asymmetric coplanar waveguide with a transverse array of unopened slots etched on a ground plane. Such structures are characterized by several cut-off frequencies on the transmission parameters. With a low dc magnetic field of 72 kAm−1 applied along with the slots, significant nonreciprocal effects greater than 20, 19 and 29 dB are obtained at 13.95, 23.39 and 39.61 GHz, respectively. The proposed structure can be used as a multiband isolator for microwave applications. The low biasing field of this multiband isolator and its compactness (88 mm2) are its main advantages, which makes this structure particularly suitable for integration.

Asymmetric frequency reconfigurable compact antenna using CRLH-TL structure

ABSTRACT An asymmetric coplanar waveguide fed frequency reconfigurable antenna based on composite right/left-handed transmission line is presented in this paper. The antenna is a composite right/left-handed transmission line composed of the meander line and a PIN diode. By controlling the switch of the PIN diode the antenna can change the frequency. Simulation and experimental results show that the −10 dB impedance bandwidth can change from 3.25–5.63 GHz to 2.73–2.96 GHz and 5.0–5.4 GHz. The antenna has good omnidirectional radiation in the working frequency band. The antenna can be widely used in WLAN and WiMAX.

Compact filtering antenna using asymmetric CPW-fed based CRLH structure

Compact filtering antenna using composite right/ left-handed (CRLH) transmission line structure is presented in this paper. It utilizes a simplified asymmetric coplanar waveguide (CPW) feeding method. Initially, a bandpass filter has been designed with a circular interdigital capacitor, meander line and rectangular patches with asymmetric CPW feeding. The filtering antenna structure has been designed by replacing the rectangular patch and coupling at load side (Port-2) of the designed filter with L-shaped patch, which acts as a radiating element. The resonance frequency can be controlled by the series parameter due to shorted boundary condition of the structure. The designed filtering antenna resonates at 3.4 GHz with 10-dB impedance bandwidth of 23.5%. It provides a nearly flat gain response within the passband by the average value of 2.5 dB along with two radiation null at 2.1 GHz and 4.5 GHz. The total size of the designed structure is 0.39λg × 0.26λg at the resonance frequency (3.4 GHz) of the working band. It gives an omnidirectional radiation pattern at the resonance frequency. The designed prototype is fabricated and measurements are done for validation of simulated results and the filtering antenna is made useful for sub-6 GHz of 5G (3.3–3.6 GHz) applications.

Asymmetric CPW-fed electrically small metamaterial- inspired wideband antenna for 3.3/3.5/5.5 GHz WiMAX and 5.2/5.8 GHz WLAN applications

In this work, a new concept is introduced to enhance the bandwidth of metamaterial (MTM) inspired antenna. The MTM inspired antenna mainly comprises a single split-ring resonator and a hexagonal-shaped closed ring resonator with asymmetric coplanar waveguide feed, which leads to antenna compactness. The physical dimension of the intended antenna is 17 mm × 20 mm × 1.6 mm. Due to MTM loading, the antenna achieves more compactness with ka = 0.87 < 1 resulting in a smaller electrical dimension of 0.18λ0 × 0.21λ0 × 0.017λ0 at 3.24 GHz. The intended antenna provides a wider bandwidth ranges from 3.06 GHz to 5.89 GHz with a percentage impedance bandwidth of 63.24% due to the merging of two resonating modes into a single passband. The proposed antenna provides a gain greater than 2 dBi for the entire working band with a maximal gain of 3.65 dBi at 5.2 GHz and radiation efficiency greater than 85% for the complete working band. Also, the antenna shows a consistent radiation pattern throughout the working band and hence the intended antenna is appropriate for 5.2/5.8 GHz WLAN IEEE 802.11 a/h/j/y, and 3.3/3.5/5.5 GHz WiMAX IEEE 802.16e applications.

A compact broadband coplanar waveguide fed circularly polarized printed monopole antenna with asymmetric modified ground plane

In this communication, a broadband circularly polarized (CP) monopole antenna with coplanar waveguide (CPW) feeding is proposed. It consists of a modified rectangular monopole, an asymmetric ground plane, a two-linked inverted L-shaped strips on the left CPW ground, and two rectangular horizontal slots in asymmetric CPW ground plane. The overall dimension is only 0.47λ o × 0.47λ o. The antenna prototype has been fabricated. The measured results indicate that a broad −10 dB impedance bandwidth (IBW) of 107.5% (4.3 GHz, 1.85-6.15 GHz) and a broad 3 dB axial ratio ARBW of 104.3% (4 GHz, 1.855-5.9 GHz) can be achieved; the average realized gain is 2.3 dBi for the entire CP band. The proposed antenna is an attractive candidate for several wireless communication systems.

A novel miniaturized asymmetric CPW split ring resonator with extended field distribution pattern for sensing applications

Novel modified split-ring resonator (SRR) for expanded field distribution and miniaturized dimensions for sensing with double sided detection capability is proposed. The proposed design is based on an asymmetric coplanar waveguide type SRR and demonstrate a smaller radius of 0.035 × λ with a resonance of 1.57 GHz at its first harmonic. The proposed structure has the potential of higher sensitivity, requires smaller sample volume and is miniaturized compared to the conventional ring resonators. The long but narrow overlap gaps evident in the proposed miniaturized SRR create capacitive and inductive contributions for better sensing performance regime and optimized for superior efficiency and miniaturization capability. For sensitivity evaluation, a coplanar SRR prototype operating at the same resonance is compared with the proposed miniaturized coplanar SRR to underscore its superior performance profile. The resulting design is prototyped on RO3003 microwave laminate with dielectric permittivity (ℇr) of 3 and measured. Sensitivity analysis is conducted by loading the both resonator on both planes with Teflon cladding sample of permittivity of 2.33, thickness of 3 mm and the results are compared. The final design is validated by loading the proposed resonator with a 0.05λ × 0.05λ sq.m and a strip of 0.045λ × 0.015λ sq.m moisture-responsive commercially available 3 M transparent water-soluble wave solder tape 5414 Poly-vinyl alcohol (PVA) film having a thickness of 20 μm.

Asymmetric CPW Fed Miniaturized dual polarized monopole Antenna for WLAN/WiMAX Applications

An Asymmetric coplanar waveguide (CPW) Fed Miniaturized dual polarized (linear Polarized and Circularly Polarized) monopole Antenna Implemented. The Inverted-L Strip monopole antenna and the asymmetric ground plane for WLAN/Wi MAX applications are presented. Monopole antenna mainly icludes asymmetric ground plane which are fed with Coplanar Wave inverted L-shape strip and a slit embedded on the ground plane providing an orthogonal phase difference were designed to generate CP radiation. Inverted-L shape strip resonance and matching condition are examined by high-frequency structure simulator (HFSS) and the prototype is designed and measured. The measure simulated results shows that the monopole antenna impedance band-width with at −10 dB of 92.5 %( 3.36-6.66GHz) and a 3-dB axial-ratio bandwidth of 53.9 %( 5.4 -6.39 GHz) could be completed which could absolutely cover the WLAN (5.725 GHz - 5.85 GHz) band. Meanwhile, a linear polarization is also bought which could absolutely cover the WiMAX (3.3 GHz -3.7 GHz) bands. Orthogonal phase difference and average peak gain for lower band 1.9 dB and upper band 2.48 dB have been achieved, respectively.

A triple‐band dual‐polarized CRLH antenna for wireless applications

AbstractThis paper presents an asymmetric coplanar waveguide fed triple‐band (1.99, 4.06, and 5.23 GHz) dual polarized antenna based on composite right‐ and left‐handed transmission line (CRLH‐TL) approach. The two lower bands of the antenna are linearly polarized whereas the rest is circularly polarized (CP). 20.49% 3 dB axial ratio bandwidth is achieved for the CP band which is higher than the recently reported triple band CRLH‐TL antennas. It has a compact size of 0.085 × 0.097 × 0.01λ0, where λ0 is the free space wavelength at ZOR frequency (1.99 GHz). The antenna is suitable for UMTS/WCDMA/PCS, WiMAX, and WLAN/Wi‐Fi applications.

Circularly polarized ACPW Fed CRLH-TL based ZOR antenna with band notch characteristics

AbstractIn this paper, two asymmetric co-planar waveguide (ACPW) fed circularly polarized (CP) zeroth-order resonance (ZOR) antennas (Antenna I and II) are presented using a composite right and left-handed transmission line (CRLH-TL) approach. By adding a stub on the left side of the ACPW ground and adjusting its length, circularly polarization property has been achieved in Antenna I. The simulated 3 dB axial ratio bandwidth (ARBW) of Antenna I is 1750 MHz (3.50–5.25 GHz). Next, the left side ground plane of Antenna I is further defected by etching a quarter wavelength slit to introduce a notch band (Antenna II). Antenna II has an extended 10 dB return loss bandwidth of 2200 MHz (3.28–5.48 GHz) with a band notch from 4.18–4.65 GHz that isolates the WiMAX and 5.2 GHz WLAN bands. ARBWs of 1080 and 870 MHz are achieved in the first and second band of Antenna II. The overlapping 3 dB ARBW and 10 dB return loss bandwidths of Antenna II in these two bands are 770 and 830 MHz, respectively.

Coplanar waveguide‐fed electrically small dual‐polarized short‐ended zeroth‐order resonating antenna using Ω‐shaped capacitor and single‐split ring resonator for GPS/WiMAX/WLAN/C‐band applications

This work explains the design and analysis of a triple-band electrically small (ka = 0.56 < 1) zeroth-order resonating (ZOR) antenna with wideband circular polarization (CP) characteristics. The antenna compactness is obtained due to ZOR frequency of composite right/left-handed (CRLH) transmission line (TL) and wideband CP radiation are achieved due to the introduction of single-split ring resonator and asymmetric coplanar waveguide fed ground plane. The proposed antenna obtains an overall electrical size including the ground plane of 0.124 λ0 × 0.131 λ0 × 0.005 λ0 at 1.58 GHz and physical dimension of 23.7 × 25 × 1 mm3 are achieved. The antenna provides a size reduction of 44.95% compared to a conventional monopole antenna. The novelty behind the ohm-shaped capacitor is the generation of extra miniaturization with better antenna compactness. The antenna provides dual-polarized radiation pattern with linear polarization radiation at 1.58 and 3.54 GHz, wideband CP radiation at 5.8 GHz. The antenna measured results shows good impedance bandwidth of 5%, 6.21%, and 57.5% for the three bands centered at 1.58, 3.54, and 5.8 GHz with a wider axial ratio bandwidth (ARBW) of 25.47% is obtained in the third band. The antenna provides a higher level of compactness, wider ARBW, good radiation efficiency, and wider S11 bandwidth. Hence, the proposed antenna is suitable for use in GPS L1 band (1.565-1.585 GHz), WiMAX 3.5 GHz (3.4-3.8 GHz) GHz, WLAN 5.2/5.8 GHz (5.15-5.825 GHz), and C-band (4-8 GHz) wireless application systems.

Compact metamaterial inspired conformal dual‐band antenna loaded with meander lines and fractal shaped inductor for Wi‐Fi and WiMAX applications

In this study, a novel metamaterial inspired compact cylindrical conformal dual-band antenna with a shunt fractal inductor and bottom patch is proposed. The conformal antenna consists of three meander lines type unit cells of composite right/left-handed metamaterials for modification and compactness. To improve the operating bandwidth in the first band i.e at 2.45 GHz, a shunt fractal inductor with large inductance is proposed. A similar patch with a slot along the bottom side is additionally used for better impedance matching. The second band at 3.5 GHz is obtained due to the loading of two meander line unit cells on the patch as parasitic elements. The proposed conformal antenna is placed on a 15 mm radius cylinder whose equivalent planar dimension is 0.48λg × 0.36λg (where λg is the guided wavelength). Asymmetrical coplanar waveguide feed is implemented. Measurement results showed that the proposed cylindrical conformal antenna achieves a wideband −10 dB fractional bandwidth of 44.5% and a gain of 1.26 dBi at the operating frequency of 2.45 GHz and 4.5% of bandwidth and a gain of 2.2 dBi at the 3.5 GHz. The radiation efficiency is 70 and 86% at the said frequencies respectively. There is good agreement between measured and simulation data.