Compact Coplanar Waveguide Research Articles

Coplanar waveguide fed inverted slot hybrid square ring antenna

ABSTRACT This paper presents a compact coplanar waveguide (CPW) fed inverted T slot loaded hybrid square ring antenna for Amateur radio (HAM) application. The CPW feed line is configured with unique characteristics: lower radiation leakage, wider bandwidth, and less dispersion than microstrip lines. The antenna is low-profile and inexpensive. The antenna design occurs in High-Frequency Structure Simulator (HFSS) simulation software and attains a S11 of −10 dB. The CPW-fed hybrid square ring antenna is considered in this research, and the antenna is embedded with inverted T slots. The antenna is constructed using a Flame Retardant 4 (FR4) substrate with a thickness of 1.4 mm and tangent losses of 0.019. The key parameters of gain, radiation pattern (RP), voltage standing wave ratio (VSWR), S11, and surface current (SC) are examined. The S11 of the designed antenna is −16.07 dB, VSWR is 1.37, and the gain is 3.6 under the operating frequency range of 2.45 GHz, and the designed antenna is suitable for HAM radio applications. The radiation pattern was analysed for the E and H planes under both the measured and the simulation scenarios. The simulation results are obtained via the HFSS platform, and the fabricated measurements are in accordance with each other.

Compact Liquid Crystal Polymer Based Tri-Band Flexible Antenna for WLAN/WiMAX/5G Applications

In this paper, a new compact coplanar waveguide (CPW)-fed liquid crystal polymer (LCP) based tri-band antenna is presented and fabricated for Wireless Local Area Network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX) and 5th-Generation (5G) systems. The antenna combines two strips with the main radiation rectangular patch and coplanar waveguide ground. The proposed antenna is printed on a LCP substrate with a thickness of 0.1 mm and has a small overall dimensions of 20mm×32mm×0.1mm. To analyze the characteristics, the antenna is designed and fabricated, and then the performance of the antenna is measured and tested. The measurement results show that the proposed antenna has three operating bandwidths, including 2.38-2.79 GHz, 3.27-4.05 GHz, and 4.80-8.44 GHz. To test the flexibility of the antenna, the antenna is simulated and measured in bent configurations for radii of 10 mm and 50 mm. In addition, the antenna is attached to different parts of the human body to test the integration effect in wearable equipment. The experimental results show that the performance of the antenna remains reliable under bending conditions and that the specific absorption ratio (SAR) value meets the European Union (EU) standard. The proposed antenna shows reasonable gains and good radiation characteristics in the operating bands. The flexible, compact, simple design and multiband performance indicates that the antenna is suitable for integration in flexible electronic devices.

Compact Coplanar Waveguide Antenna Using Arm Patch for Software Defined Radio

This article proposes a compact coplanar waveguide (CPW) antenna with a semicircular patch and patch arm above the feed line. The method used in this antenna research is experimental, with antenna parameter optimization, fabrication, and measurement steps. The antenna was 40 mm × 46 mm × 0.8 mm and was printed on an FR4 substrate. Antenna optimization was carried out with CST Studio Suite to obtain optimal results. Based on return loss measurement results, the proposed antenna has an operational frequency of 2 GHz–7 GHz. The antenna arm has a significant effect on the operational frequency of the antenna, as proven by a parameter study of the antenna arm. Parametric studies were carried out on the antenna by investigating the influence of geometric parameters on the frequency characteristics. Optimization results were printed then measured by a Vector Network Analyzer (VNA) and a spectrum analyzer. The fabricated CPW antenna has a wider operating frequency than the simulation. An omnidirectional radiation pattern was observed at 2 GHz–4 GHz. The antenna has been used as a transmitter and receiver at 2.4 GHz, 3 GHz, and 4 GHz. The antenna is able to receive the signal emitted from the signal generator.

Bandwidth and Gain Enhancement of a CPW Antenna Using Frequency Selective Surface for UWB Applications

In this article, a single-layer frequency selective surface (FSS)-loaded compact coplanar waveguide (CPW)-fed antenna is proposed for very high-gain and ultra-wideband applications. At the initial stage, a geometrically simple ultra-wideband (UWB) antenna is designed which contains CPW feed lines and a multi-stub-loaded hexagonal patch. The various stubs are inserted to improve the bandwidth of the radiator. The antenna operates at 5-17 GHz and offers 6.5 dBi peak gain. Subsequently, the proposed FSS structure is designed and loaded beneath the proposed UWB antenna to improve bandwidth and enhance gain. The antenna loaded with FSS operates at an ultra-wideband of 3-18 GHz and offers a peak gain of 10.5 dBi. The FSS layer contains 5 × 5 unit cells with a total dimension of 50 mm × 50 mm. The gap between the FSS layer and UWB antenna is 9 mm, which is fixed to obtain maximum gain. The proposed UWB antenna and its results are compared with the fabricated prototype to verify the results. Moreover, the performance parameters such as bandwidth, gain, operational frequency, and the number of FSS layers used in the proposed antenna are compared with existing literature to show the significance of the proposed work. Overall, the proposed antenna is easy to fabricate and has a low profile and simple geometry with a compact size while offering a very wide bandwidth and high gain. Due to all of its performance properties, the proposed antenna system is a strong candidate for upcoming wideband and high-gain applications.

New Design of a Compact 1×2 Super UWB-MIMO Antenna for Polarization Diversity

This paper proposes a new design of compact coplanar waveguide (CPW) fed -super ultra-wideband (S-UWB) MIMO antenna with a bandwidth of 3.6 to 40 GHz. The proposed antenna is composed of two orthogonal sector-shape monopoles (SSM) antenna elements to perform polarization diversity. In addition, a matched L-shaped common ground element is attached for more efficient coupling. The FR-4 substrate of the structure with a size of 23 × 45 × 1.6 mm3 and a dielectric constant of 4.3 is considered. The proposed design is simulated by using CST Microwave Studio commercial software. The simulation shows that the antenna has low mutual coupling (|S21| < -20 dB) with |S11|<−10 dB, ranging from 3.6 to 40 GHz. Envelope correlation coefficient (ECC) is less than 0.008, diversity gain (DG) is more than 9.99, mean effective gain (MEG) is below – 3 dB, and total active reflection coefficient (TARC) is less than -6 dB over the whole response band is reported. The proposed MIMO antenna is expected efficiently cover the broadest range of frequencies for contemporary communications applications.

Compact 26–30 GHz Reflection-Type Phase Shifter With 8-Bit Switched Phase Tuning Utilizing Chalcogenide Phase-Change Switches

This article reports the first implementation of a 8-bit millimeter-wave (mmWave) reflection-type phase shifter (RTPS) based on phase change material (PCM) germanium telluride (GeTe). The switched phase shifter employs a compact co-planar waveguide (CPW)-based quadrature coupler in folded tandem configuration monolithically integrated with two identical reconfigurable reflective loads optimized to achieve a large phase shift range. Reconfigurability is achieved using eight identical latching PCM switches to load or unload a desired reflective load while consuming no static dc power. Various reflective load topologies are investigated for the optimum phase shift range over the operational bandwidth. The reflective load consists of either high-frequency metal-insulator-metal (MIM) capacitors. The resonance frequency of various states is pushed beyond 40 GHz to get a resonance-free tuning zone. The fully integrated phase shifter is highly miniaturized with an overall device footprint under <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.98\times0.9$ </tex-math></inline-formula> mm, fabricated using an eight-layer in-house microfabrication process. The mmWave phase shifter demonstrates measured average insertion loss of 5.25 dB with only ±0.75 dB loss variation over 4 GHz bandwidth at 28 GHz center frequency. The proposed phase shifter exhibits a measured 280° linear phase shift in 256 discrete precision steps over 26 to 30 GHz with a figure-of-merit (FoM) of 53.3°/dB.

Printed compact four-port wearable MIMO antennas for wideband wireless applications

AbstractIn this paper, a simple and compact coplanar waveguide (CPW)-fed four coexisting inverted-L-shaped radiating elements based wideband (ILW) multi-input and multi-output (MIMO) antenna has been presented for wearable wireless applications. The 50 Ω CPW feed structure has been used to excite the four inverted-L-shaped radiators in a wide square slot of the proposed four-port wearable MIMO antenna. The four diagonal strips are extended from the corners of the wide square slot to form a square split ring structure in the center, which suppresses the coupling of electromagnetic waves among coexisting compact quad inverted-L-shaped radiators. The proposed ILW wearable MIMO antenna achieves a wide −10 dB simulated impedance bandwidth of 58.18% (3.9–7.1 GHz) and more than 30 dB isolation along with much reduced envelope correlation coefficient (&lt;0.0002), high diversity gain (&gt;9.9 dB), and specific absorption rate lower than 1 W/kg in the entire operational band. The simulated results are in good agreement with the measured ones. This ensures its utility for several wearable wireless applications in the C-band that comprises WLAN (5 and 5.2 GHz), Wi-MAX (5.5 GHz), and ISM band (5.8 GHz) applications.

Compact Cauliflower-Shaped Antenna for Ultra-Wideband Applications

A compact coplanar waveguide (CPW) fed cauliflower-shaped antenna is presented and discussed in this paper. To extend the impedance bandwidth and to improve the impedance matching, fractal geometry having a cauliflower shape is introduced along the edges of the radiator. To validate the simulated results by experimental ones, a prototype of the designed antenna was fabricated on the RO-4350B substrate having a compact size of 0.3623λ0 × 0.41λ0 × 0.01524λ0 at 3 GHz. An Agilent 8722ES vector network was used for the reflection coefficient measurement revealing that the –10 dB bandwidth of the fabricated antenna offers an impedance bandwidth of 113% extending from 3.05 to 10.96 GHz. Besides, the antenna’s radiation patterns are measured in an anechoic chamber showing consistent radiation patterns characteristic over the entire working band. Furthermore, the proposed antenna has a peak gain of around 6 dBi and an average radiation efficiency almost over 90% across the entire operating band. Thus, the proposed antenna could be useful in many modern ultra-wideband (UWB) communication systems.

Compact Dual Band and Dual Polarized CPW-Fed Triangular Shaped Wearable Antenna for ISM band Applications

ABSTRACT A coexisting compact dual coplanar waveguide (CPW)-fed dual-band and dual-polarized triangular-shaped wearable antenna (TSWA) is proposed for 2.45 GHz and 5.8 GHz ISM (Industrial, Scientific and Medical) frequency bands. The proposed antenna of area 722 mm2 is fabricated on polyimide substrate (thickness of 1.6 mm and relative permittivity of 3.5). The two identical inverted-L-shaped feed stubs are employed orthogonally in wide triangular slot to provide both horizontally and vertically polarized radiations in both ISM bands. An additional Y-shaped copper strip is introduced to isolate the two inverted-L-shaped feed stubs in order to achieve higher isolation in both 2.45 and 5.8 GHz operational frequency bands. The proposed TSWA achieves similar −10 dB impedance bandwidths of 21.7% (2.30 ̶ 2.86 GHz) and 14.26% (5.60 ̶ 6.46 GHz) respectively for dual-polarized radiations along with more than 20 dB isolation in both 2.45 and 5.8 GHz ISM bands. The effect of human loading on performance of proposed TSWA is also studied. The proposed antenna is designed, fabricated, and tested. The simulated results are verified and validated with measured ones and thus, makes it suitable for wearable ISM bands applications.

A Compact CPW-Fed Ultra-Wideband Multi-Input-Multi-Output (MIMO) Antenna for Wireless Communication Networks

In this article, a compact coplanar waveguide (CPW) technique based ultra-wideband multiple-input-multiple-output (MIMO) antenna is proposed. The design is characterized by a broad impedance bandwidth starting from 3 GHz to 11 GHz. The overall size of the MIMO design is <inline-formula> <tex-math notation="LaTeX">$60\times60$ </tex-math></inline-formula> mm² (<inline-formula> <tex-math notation="LaTeX">$1.24\times 1.24\,\,\lambda _{g}^{2}$ </tex-math></inline-formula> &#x0040; 3 GHz) with a thickness of 1.6 mm. To make the design ultra-wideband, the proposed MIMO antenna design has four jug-shaped radiating elements. The design is printed on a FR-4 substrate (relative permittivity of <inline-formula> <tex-math notation="LaTeX">$\varepsilon _{r} = 4.4$ </tex-math></inline-formula> and loss tangent of <inline-formula> <tex-math notation="LaTeX">$\mathrm {tan}\delta = 0.025$ </tex-math></inline-formula>). The polarization diversity phenomenon is realized by placing four antenna elements orthogonally. This arrangement increases the isolation among the MIMO antenna elements. The simulated results of the ultra-wideband MIMO antenna are verified by measured results. The proposed MIMO antenna has a measured diversity gain greater than 9.98, envelope correlation coefficient (ECC) less than 0.02, and good MIMO performance where the isolation is more than &#x2212;20dB between the elements. The group delay, channel capacity loss (CCL), and the total active reflection coefficient (TARC) multiplexing efficiency and mean effective gain results are also analyzed. The group delay is found to be less than 1.2ns, CCL values calculated to be less than 0.4 bits/sec/Hz, while the TARC is below &#x2212;10dB for the whole operating spectrum. The proposed design is a perfect candidate for ultra-wideband wireless communication systems and portable devices.

UWB CPW fed 4-port connected ground MIMO antenna for sub-millimeter-wave 5G applications

This paper embodies the design and development of a compact Coplanar Waveguide (CPW) fed connected ground Multiple- Input-Multiple-Output (MIMO) antennas operating in the sub-millimeter-wave 5G New Radio (NR) n257/n258/n261 bands. The planar geometry leads to a small and compact structure while achieving a wide operating bandwidth, high gain, and better radiation efficiency. The top surface of the antenna comprises a modified CPW in the form of two circular structures that feeds the centrally slotted circular patch. The single antenna structure is arranged in a rotational orthogonal manner forming a 4-port structure. The ground plane on the bottom of a 4-port structure is connected using a circular ring which is carefully optimized for achieving isolation levels>20 dB across the band of interest. The sub-mm-wave resonating 4-port antenna achieves a compact size of 24 × 24 mm2, a wide bandwidth of 24.8–44.45 GHz (79.35%), the maximum gain of 8.6dBi, and minimum efficiency of 85% across the bands of interest. The proposed antenna element is fabricated over Rogers 5880 substrate and experimental tests are carried out, where a good correlation between the scattering parameters, transmission parameters, gain, and MIMO diversity performance is achieved that makes the antenna a potential candidate for its application in sub-millimeter wave 5G applications.

A compact coplanar waveguide dual-band bandpass filters based on defected ground structures

A compact coplanar waveguide dual-band bandpass filters based on defected ground structures

Design a compact CPW monopole antenna on rubber substrate for ISM band application

One of the most challenging works on compact antenna design is to maintain the flexibility orientation. This paper demonstrates a coplanar waveguide (CPW) fed monopole antenna with rubber substrate at 2.45 GHz center frequency for ISM band application. The proposed antenna attained the realized gain at 4.06 dB with the radiation efficiency around 90% at peak value and the bandwidth of 541.5 MHz. The antenna was designed using the CPW structure. CST microwave studio applied to design the proposed antenna simulation. The main purposed of this study is to improve the antenna performances specially the bandwidth, gain, and radiation efficiency. Moreover, another aim of that antenna design is to reduce the antenna size and thickness upon the existing related design with rubber substrate.

A novel flexible hexagon wideband CPW‐fed monopole antenna for UWB applications

AbstractThis article proposed a novel compact coplanar waveguide (CPW) fed flexible wideband antenna. The antenna is composed of hexagonal radiation patch, rectangular slots and trapezoid ground. The antenna works in 5.2–41 GHz (154.98% fractional bandwidth) range with a return loss of −10 dB. Based on thin liquid crystal polymer (LCP), the antenna has an overall size of 23.6 mm × 15.4 mm × 0.1 mm. The presented antenna is planned and optimized through High Frequency Structure Simulator (HFSS). The simulated and measured results exhibit good characteristics in terms of reflection coefficients, peak gain, and radiation patterns. The designed antenna can be used in ultra‐wideband (UWB) systems and C‐band (4–8 GHz), WLAN (5.2–5.8 GHz), X‐band (8–12 GHz), Ku‐band (12–18 GHz), K‐band (18–27 GHz), Ka‐band (27–40 GHz), and millimeter wave (MMW).

Coplanar Waveguide-fed UWB Slotted Antenna with Notched-band Performance

Compact coplanar waveguide Ultra-wideband (UWB) monopole antenna with band notched characteristics is presented in this paper. The band rejection is achieved by etching a circular slot on the radiating patch. The antenna is printed on the FR4-Epoxy substrate with overall dimensions of 23.5 × 31 × 1.5 mm3. The measured results indicate that the antenna operates in the frequency range from 1.76 to 11.07 GHz and rejects the band 2.42 to 5.37 GHz with an acceptable measured input impedance over the whole operating frequency bandwidth. Furthermore, the simulated results indicate that the antenna exhibits stable radiation patterns with appreciable gain and efficiency over the whole operating band except at the notched-band. Accordingly, this antenna provides a good solution for wireless communication systems with good characteristics.

A compact CPW-fed band-notched UWB-MIMO flexible antenna for WBAN application

A compact coplanar waveguide (CPW)-fed band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) flexible antenna on liquid crystal polymer (LCP) substrate is designed. It is composed of two orthogonal elements, tampered feeder and asymmetric ground plate. To improve the port isolation (S 21), an inverted F-shaped branch is added. The measurement results demonstrate that the antenna has achieved impedance bandwidths (S 11 < −10 dB) of 890 MHz (2.4–11.3 GHz) except one rejected band of 3.1–4.3 GHz, and the port isolation is higher than 23 dB. The influence of human body and bending have also been experimented. The results show that the designed antenna has satisfactory bandwidth, high isolation, sound gain in working bands, the characteristics of flexibility and low specific absorption ratio (SAR) values, which indicate the excellent application in the WBAN systems.

A novel type of wearable dual-band antenna based on coplanar waveguide feeding for wearable wireless communications

A flexible and compact coplanar waveguide feed (CPW-fed) wearable antenna is introduced for wireless wearable communications applications at the industrial scientific medical (ISM) band. The proposed antenna consists of copper, which is used as the radiation patch and ground planes printed on the same side of polyimide flexible substrate. The overall size of the antenna is 30 mm × 28 mm × 0.08 mm, the results show that the antenna can transmit and receive signals in two frequency bands of 1.89–2.67 GHz and 3.02–3.23 GHz, in which radiating properties are characterized and agree well with the simulation results. The antenna is bent in different directions to further investigate the reflection coefficient and corresponding effect on the antenna under bending. The center frequency of the antenna is slightly shifted towards higher and lower frequencies when antenna is bent in X-axis and Y-axis, respectively. Furthermore, the wearability of the antenna is verified when the antenna is placed on different parts of the human body such as wrist and chest. Hence, the proposed flexible antenna is a suitable candidate for wearable wireless communication applications.

A Compact Eight-port CPW-fed UWB MIMO Antenna with Band-notched Characteristic

A compact eight-port coplanar waveguide (CPW)-fed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with band-notched characteristics in a small size of 54×54×0.8 mm3 is proposed in this paper. The eight-port MIMO antenna consists of four two-port MIMO antennas. For each two-port MIMO antenna, two monopole antenna elements are printed on the FR4 substrate and placed perpendicularly to each other. To increase impedance bandwidth and improve the isolation, a stub is positioned in the middle of two radiating elements. The band-notched characteristic are achieved by etching two L-shaped resonator slots on each radiating elements, respectively. The S11 reflection coefficients, coupling isolation, radiation patterns, peak gain and radiation efficiencies of the MIMO antenna are measured. The MIMO performance of the proposed antenna is analyzed and evaluated by the envelope correlation coefficient (ECC) and total active reflection coefficient (TARC).

Compact coplanar waveguide fed wideband directional antenna for medical diagnosis

This paper presents a compact coplanar waveguide fed antenna for medical diagnosis of the human head. Early diagnosis of the sophisticated organs inside the human body is possible through microwave medical imaging, which has recently achieved its popularity due to its numerous advantages. The crucial functional element for microwave medical imaging is the antenna. The antenna presented in this paper is conceived and evaluated in contact with an inhomogeneous human head tissue medium, increasing the signal penetration by removing the antenna–air–tissue transition loss. A combination of a meandered line and circular slot are utilized to achieve wideband performance at a subwavelength size. A rectangular cavity is introduced at the back of the antenna to attain directional radiation towards the inhomogeneous human head phantom. The antenna achieves increased bandwidth covering the lower microwave frequency region for medical diagnosis of a human head while minimizing ill-directed radiated fields which interfere with imaging computations. The salient characteristics of compact size, high near-field directionality, lower microwave operating frequency range and low impact on the skin surface make the proposed antenna a suitable candidate for microwave imaging of the human head.

Coplanar waveguide fed compact dual-band antenna with capacitive shorting between signal strip and ground plane

A compact coplanar waveguide fed dual-band antenna using capacitive shorting between the signal strip and the ground plane is presented in this paper. The antenna achieves dual-band properties by making slots on the ground plane and capacitive shorting between the center feed and the ground plane through the slot. The proposed antenna occupies an area of 0.122λ01 × 0.134λ01 mm2 (λ01 is the free space wavelength of the first resonant frequency) and is printed on a substrate of relative permittivity 4.3 and thickness 1.6 mm. The experimental analysis shows a − 10 dB impedance bandwidth up to 6% and 30% for the first and second resonance bands respectively. The antenna radiation characteristics like reflection coefficient, 2D radiation pattern, gain and efficiency are measured and satisfy the requirements for ISM 5.2, ISM 5.8 and WLAN applications.