Planar Ultra-wideband Antenna Research Articles

Fractal Cross-Slot-Coupled Antenna with Dielectric Resonator Elements having Circular Polarization

This article presents the design and analysis of an “ultra-wideband (UWB)” Fractal Cross-slot-Coupled Antenna with “Dielectric Resonator Elements (DREs)” exhibiting circular polarization and band-notched characteristics. The proposed antenna aims to reject the frequency range of 5.1 GHz to 5.9 GHz while maintaining high impedance bandwidth and radiation efficiency. A coplanar waveguide feeds the planar UWB antenna, featuring a narrow slot on the radiating element and a dielectric resonator mounted on top. Simulation results demonstrate excellent performance in terms of impedance bandwidth and radiation efficiency. To further improve the design for wireless applications, Fractal-slot-aperture coupled DRE antennas are employed. The proposed configuration takes into account the radiative efficiency and concomitant excitation of the rectangular DRE by a “Circularly Polarized Dielectric Resonator Antenna (CPDRA)” coupled through a fractal cross-slot. By appropriately adjusting the fractal cross-slot size, a wider “axial ratio (AR)” bandwidth is achieved through the combination of its resonance with the dielectric resonator. The antenna is designed utilizing the proposed fractal cross-slot-coupled CPDRA, with its architecture and efficiencies thoroughly investigated. The performance of the proposed antenna demonstrates its potential for various wireless communication applications, highlighting the advantages of integrating Fractal Cross-slot-coupled DREs in antenna design.

Improving gain of ultra-wideband planar antennas: a grounded frequency-selective surface reflector

Improving gain of ultra-wideband planar antennas: a grounded frequency-selective surface reflector

High-Efficiency Full-Metal Planar Slot Array Antenna With Over 60% Bandwidth

This letter presents an ultra-wideband full-metal planar array antenna with over 60% fractional bandwidth (FBW). A single-ridge waveguide excited semi-open radiating slot is firstly designed to achieve wideband property. Then, the full-corporate feeding network, consisting of a cavity-backed layer and a planar power divider layer, is implemented based on the single-ridge waveguide to suppress the reflection in a wideband. An ultra-wideband planar array antenna is finally constructed combining these aforementioned components. An 8 × 8-element array prototype is designed, fabricated and measured, and the experimental results indicate that the impedance matching bandwidth covers 17 - 32 GHz (FBW of 61.2%). A peak gain of over 22.7 dBi and an aperture efficiency of over 81% have been achieved within the entire operating frequency band.

Low-RCS UWB Planar Monopole Array Antenna Based on the Optimized Design of the Conductor Layers

Using an optimized design of combining traditional copper (Cu) film and novel phase transition film vanadium dioxide (VO2), this communication proposes an ultrawideband (UWB) planar monopole array antenna with excellent stealth performance. The VO2 film exhibits two controllable phases: one with low conductivity of less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{3}$ </tex-math></inline-formula> S/m and the other with high conductivity of more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{6}$ </tex-math></inline-formula> S/m. Since VO2 has lower conductivity than Cu, antenna designs using this material will have lower radiating efficiency as a tradeoff for reducing the radar cross Section (RCS). To optimize this tradeoff, careful antenna shape design, and an innovative combination of using VO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{2}+$ </tex-math></inline-formula> Cu films, the RCS can be reduced in a UWB without significantly decreasing the gain of the array antenna. In this work, Cu is applied in the regions supporting high current density, while phase transition VO2 film is used in areas supporting lower current density. Both the shape and size of the VO2 film are optimized. Compared with the all-Cu film counterpart, the realized gain of the VO <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{2}+$ </tex-math></inline-formula> Cu hybrid film array antenna is decreased only by an average of 0.4 dBi, maintaining the same radiation pattern in the working band of 6–9 GHz, while the monostatic RCS is reduced by about 9 dB on average across the UWB of 4–11 GHz.

Super Ultra-Wideband Planar Antenna with Parasitic Notch and Frequency Selective Surface for Gain Enhancement

A compact Super ultra-wideband (SUW) antenna is discussed in this work. A rectangular radiator is modified into a tree-shaped structure with the defected partial ground to enhance the operating bandwidth. The novel rectangular parasitic with the circular slot is used as a notch in the ground plane which prevents the WLAN frequency. The proposed SUW antenna is achieving the 10 dB impedance bandwidth (IBW) from 3.5 GHz to 66.5 GHz frequency with a notched band varying from 5.0 GHz to 5.4 GHz. The bandwidth ratio (BDR) of the proposed SUW antenna is 1773.4 whereas the obtained bandwidth percentage (BW %) is 180. A modified SRR frequency selective surface (FSS) is designed for UWB application to improve the gain of the antenna. The compact unit cell of FSS is having electrical dimensions of 0.16λ0x 0.16λ0 The antenna achieves the maximum realized gain 9.46 dB when FSS is loaded as a superstrate and up to 5.2 dB gain enhancement is observed in the UWB frequency.

Design of UWB Antenna for Multimedia and High-Speed Automotive Communication

This paper reveals a planar ultra-wideband (UWB) antenna with defective ground structure is designed and analyzed. A size of 24 × 24 × 1.6 mm3 circular shaped proposed UWB antenna uses FR-4 substrate covering the impedance bandwidth (S11 ≤ −10 dB) of 11 GHz ranging from 2.9 GHz to 13.9 GHz and also offers a peak gain of 5.1 dBi, more than 65% of efficiency in overall UWB operating band with omnidirectional radiation pattern. The simulated results of proposed UWB planar antenna have good performance, and is well-suited for high-speed and multimedia communications in vehicular environment.

A Miniaturized Microstrip Antenna for Ultra-wideband Applications

In this paper, the authors present an ultra-wideband (UWB) planar antenna with defected ground structure (DGS) for various wireless applications. The operating frequency of the proposed geometry is in the range of 3.1 to 10.6 GHz. The proposed compact geometry antenna is applicable for the UWB applications. In order to optimize the dimensions of the antenna, a parametric analysis has been performed. The measured S11 magnitude is less than -10 dB over the band, and it has an impedance bandwidth of 10.60 GHz. The designed UWB antenna gives maximum radiation efficiency and gain of 96.5% and 3.30 dBi, respectively. Also, it gives good time-domain characteristics over the entire resonating band. The designed UWB antenna is simple geometry, and it is applicable for numerous wireless applications.

A Planar Four-Element UWB Antenna Array with Stripline Feeding Network

This paper proposes a four-element ultrawideband (UWB) planar antenna array with elliptical-shaped radiators and a stripline excitation network designed for the 6–8.5 GHz UWB frequency band allowed in Europe by the European Commission. The designed antenna array has a symmetrical structure in which the radiators are placed along one line in the central conducting layer, arranged between two layers of a dielectric. Radiating elements are fed by the stripline excitation network that provides uniform power distribution. The dimensions of the elliptical radiators’ axes are 14 mm × 16 mm. Two variants of array are proposed. The distance between the radiators’ centers is L = 19 mm for a shorter variant and L = 24 mm for a longer one. The presented antenna array structures have a size of 81 mm × 41 mm and 96 mm × 41 mm. These arrays present a measured gain of 6.4–10.6 dBi for the shorter variant and 8.5–10.8 dBi for the longer one and a fair impedance matching. The measured |S11| is less than −8.7 dB and −9.7 dB for the shorter and longer corresponding variants.

Design of Dual-Band Notched UWB Antenna Loaded with Split Ring Resonators for Wide Band Rejection

ABSTRACT Nowadays, the design of a miniaturised ultra-wideband (UWB) antenna with wide dual band-notched characteristics gained widespread demand in wireless communications to reduce interference. The design of a planar CPW-fed circular UWB antenna loaded with split ring resonators and stubs is presented to eliminate two frequency bands. Two symmetrical circular split ring resonators are etched below the CPW feed at the backside of a circular UWB monopole antenna to suppress 3.61 GHz–5.57 GHz (sub-6 GHz band) wideband interference, whereas the 7.06 GHz–8.79 GHz (X-band uplinks and downlinks) band is suppressed by loading two L-shaped stubs. Slots are also made on the patch and ground to enhance impedance matching at a lower resonance frequency. The proposed notch band antenna has a compact size of 38 × 32 × 1.6 mm3 and has the highest gain of 5.75 dB at a frequency of 9 GHz. The parametric analysis has been performed to obtain optimised dimensions for better performance. The designed antenna is simulated, prototyped and tested to validate the antenna design.

High Gain of UWB Planar Antenna Utilising FSS Reflector for UWB Applications

In this paper, a high gain and directional coplanar waveguide (CPW)-fed ultra-wideband (UWB) planar antenna with a new frequency selective surface (FSS) unit cells design is proposed for UWB applications. The proposed UWB antenna was designed based on the Mercedes artistic-shaped planar (MAP) antenna. The antenna consisted of a circular ring embedded with three straight legs for antenna impedance bandwidth improvement. The modelled FSS used the integration of a two parallel conductive metallic patch with a circular loop structure. The FSS provided a UWB stopband filter response covering a bandwidth of 10.5 GHz, for frequencies from 2.2 to 12.7 GHz. The proposed FSS had a compact physical dimension of 5 mm × 5 mm × 1.6 mm, with a printed array of 19 × 19 FSS unit cells. The FSS unit cells were printed on only one side of the dielectric FR4 substrate and placed as a sandwich between the antenna and the reflector ground plane. An equivalent circuit configuration (ECC) was used to verify the FSS unit cell structure’s performance. The simulated results indicated that the UWB MAP antenna and FSS reflector provided a fractional bandwidth of 136% and a high gain of 11.5 dB at 8.5 GHz with an acceptable radiation efficiency of 89%. Furthermore, the gain was improved across the operating band and kept between 8.3 and 11.5 dB. The proposed antenna was in good agreement between theoretical and experimental results and offered a wide enough bandwidth for UWB and vehicle applications.

A boomerang-shaped UWB antenna for spectrum sensing

A boomerang-shaped ultra wide band (UWB) planar antenna has been presented for spectrum sensing applications. The presented antenna has been built upon a narrow band isotropic antenna design. In order to achieve a wider bandwidth, an exponential profile (similar to log spiral) is used. Simulation results show that the antenna has an impedance bandwidth of 163% (1.3–12 GHz) for VSWR≤2 with good radiation properties. In order to quantify the antenna performance, antenna radiation pattern and efficiency have been compared with previously reported designs. It is shown that the proposed design is able to achieve nearly omnidirectional patterns in more than one planes while achieving a maximum radiation efficiency of 92%. The overall dimensions of the proposed design are mm. The prototype of the proposed antenna is manufactured using FR4 substrate (, h = 1.6 mm).

Coplanar waveguide-fed compact planar ultra-wideband antenna with inverted L-shaped and extended U-shaped ground for portable communication devices

To simultaneously cover multiple wireless services and protocols, the antenna in communication devices should operate over a wide and ultra-wide frequency band. The use of wide/ultra-wideband antennas not only lessens the number of antennas necessary to cover multiple frequency bands but also decreases the system complexity, size, and costs. To operate over the ultra-wide frequency band, in this paper a CPW-fed small antenna is reported for portable communication devices. The anticipated antenna comprises a bow-tie-shaped patch and two ground planes. One inverted L-shaped and one extended U-shaped ground plane are asymmetrically placed with the main radiator which helps the antenna prototype to realize a functional band of 3.05 – 11.25 GHz (VSWR ≤ 2). In the functional band, the studied antenna accomplished a maximum peak gain of 4.98 dBi and maximum efficiency of 94.4%. Moreover, it exhibits symmetric omnidirectional radiation patterns and good time-domain behavior. The lucrative characteristics such as simple design, very small size (24.5 × 20 mm2), ultra-wide operating band, good gain and efficiency, stable radiation characteristics, and good time-domain characteristics make it a potential candidate to be used in portable communication devices.

Tunable Inverted U-shaped Dual Band Notch Monopole Antenna for Ultrawideband Applications

This work presents a planar ultra-wideband (UWB) monopole antenna with controllable dual-band notches. In the proposed design, the lower and upper notch characteristics are realized by placing an inverted U-shaped slot on the radiating surface and another inverted U-shaped strip near to microstrip feed line, respectively. The controllable dual-notch frequencies are attained by placing varactor diodes at an appropriate position on the inverted U-shaped slot and inverted U-shaped strip, respectively. Simulation results show that the proposed antenna design has tunable band-notch characteristics from 5.58 GHz to 5.91 GHz and 7.02 GHz to 7.45 GHz, by decreasing the capacitance value from 2.67 pF to 0.63 pF. The fabricated prototype of the optimized design is characterized in three cases. A fairly good agreement is observed between the simulated and experimental results in all three cases. To the best of the authors’ knowledge, the dual tunable band rejects UWB is proposed for the first time in this paper.

A planar CPW fed UWB antenna with dual rectangular notch band characteristics incorporating U‐slot, SRRs , and EBGs

In this article, a planar ultra-wideband (UWB) antenna with dual rectangular notchband characteristics (ie, 5.94-7.50 GHz and 8.02-10.46 GHz) is presented. The two-notch bands are chosen based on various wireless applications operating in C-band and X-band. The size of the antenna is very compact (25 × 25 × 1.6 mm3) and is designed on a low-cost FR4 substrate. Co-planar waveguide (CPW) feed and beveling techniques are utilized for achieving the UWB operation. In order to yield the first rectangular notch, a U-slot and a pair of split-ring resonators are embedded into the radiating patch and the backside of the design, respectively. The coupling between these two structures is adjusted so as to achieve a rectangular band-notch operation. The second rectangular notch has been achieved by introducing the two mushroom type electromagnetic band-gap structures on the opposite side of the CPW feed. The parametric analysis for controlling band notches, time-domain analysis, and filter synthesis is also presented. Finally, simulated as well as measured results of S11, gain, radiation pattern, group delay, and total efficiency are demonstrated to show the suitability of this design for UWB systems.

Design of a Planar Tri-Band Notch UWB Antenna for X-Band, WLAN, and WiMAX

In this work, a new ultra-wideband (UWB) antenna design with 2.08GHz to 12GHz impedance bandwidth and triple-band specifications is presented. The proposed antenna is formed by a truncated square patch, a partial ground plane, and a 50Ω microstrip line. Three different types of slots were used in order to induce notched bands. A C-shaped slot is etched on the radiating patch to obtain a notched band in 3.31-4.21GHz for WiMAX. An inverted U-shaped slot in the micro-strip line induces a second notched band in order to reduce the interference with the WLAN [5.04-6.81GHz]. Finally, two inverted L-shaped slots around the micro-ribbon line on the ground plane allow the X-band [9.13 to 10.75GHz]. The antenna has dimensions of 32×28×1.6mm3. The Ansoft software (HFSS) was used to simulate the proposed structure. The simulation results are in good agreement with the measurement results. The antenna shows an omnidirectional radiation pattern.

A Planar Ultrawideband Patch Antenna Array for Microwave Breast Tumor Detection.

In this paper, a compact planar ultrawideband (UWB) antenna and an antenna array setup for microwave breast imaging are presented. The proposed antenna is constructed with a slotted semicircular-shaped patch and partial trapezoidal ground. It is compact in dimension: 0.30λ × 0.31λ × 0.011λ, where λ is the wavelength of the lowest operating frequency. For design purposes, several parameters are assumed and optimized to achieve better performance. The prototype is applied in the breast imaging scheme over the UWB frequency range 3.10–10.60 GHz. However, the antenna achieves an operating bandwidth of 8.70 GHz (2.30–11.00 GHz) for the reflection coefficient under–10 dB with decent impedance matching, 5.80 dBi of maximum gain with steady radiation pattern. The antenna provides a fidelity factor (FF) of 82% and 81% for face-to-face and side-by-side setups, respectively, which specifies the directionality and minor variation of the received pulses. The antenna is fabricated and measured to evaluate the antenna characteristics. A 16-antenna array-based configuration is considered to measure the backscattering signal of the breast phantom where one antenna acts as transmitter, and 15 of them receive the scattered signals. The data is taken in both the configuration of the phantom with and without the tumor inside. Later, the Iteratively Corrected Delay and Sum (IC–DAS) image reconstructed algorithm was used to identify the tumor in the breast phantom. Finally, the reconstructed images from the analysis and processing of the backscattering signal by the algorithm are illustrated to verify the imaging performance.

Ultra-Wideband Planar Antenna with Notched-Band for WIMAX, WLAN and MSAT Applications

Ultra-wideband (UWB) with triple band notch characteristics was presented. WIMAX, WLAN and Meteorological Satellite (MSAT) frequency bandwidths were rejected in the UWB planar antenna composed from a single layer conductor element. Frequency bandwidths for WIMAX, WLAN and MSAT are allocated at 3.3~3.7, 5~6 and 7.4~8.4GHz, respectively. Conductor element etching method was used as the means to realize the band notch characteristics as it was considered convenient and simple. Two slits were etched on the ground plane while on the elliptical element, a single slit. The slits were designed for simplicity in the means of achieving the desired band notch characteristics. The proposed antenna design was compact and low profile. The antenna performances were compared with the reference antenna and the results were negligible.

Ultra-Wideband Antenna Development to Enhance Gain for Surface Penetrating Radar

The aim of this article is to introduce a compact configuration of an arc shape ultra-wideband (UWB) planar antenna with nominal characteristics towards surface penetrating radar (SPR). The design is implemented to enhance antenna gain and bandwidth widening, that makes it a suitable device to be used in the detection or scanning operations. To serve the purpose, a simplified defected ground structure (DGS) method is been adopted, in which different rectangular size slots were induced over the surface of the ground plane to condense the surface current distribution of the radiating patch. Furthermore, the measurements elaborated that the proposed DGS based antenna has a very wide bandwidth from 3 to 16 GHz, which is significantly greater than the defined UWB range. The resultant gain is 6.2 dB that helps in deep penetration and the wider bandwidth can carry more information, which makes the antenna a potential device to be used in detection applications. The detection capacity of antenna has been validated using monostatic and bistatic based experimental configurations. Apart from this, a simple structure and low cost fabrication of antenna makes it appropriate for SPR applications.

Antipodal tapered slot antenna array using broadband decoupling structure for mutual coupling reduction

In this article, an effective method to reduce the mutual coupling between the antipodal tapered slot antenna (ATSA) array is proposed. This method is mainly implemented by loading a set of decoupling structures (DS) perpendicular to the dielectric substrate between two antenna elements. The proposed DS can provide transmission forbidden band which can effectively prevent leaked electromagnetic waves. DS can operate in most frequency bands within 4 to 17.5 GHz. It can enhance about 23 dB isolation between the ATSA array without affecting bandwidth and radiation characteristics. The proposed ATSA arrays are fabricated and tested. The measured results can verify its excellent properties. The proposed broadband decoupling method is a suitable candidate for restrain mutual coupling of ultra-wideband planar end-fire antennas. This design sheds new light on broadband decoupling.

Multimode electric ring resonator (ERR) for ultra-wideband (UWB) antenna with multi-notch band

The electric ring resonator (ERR) is widely used for a design of metamaterials. The planar multimode ERR is considered as a promising structure for a design of multiband microwave devices. The ultra-wideband (UWB) planar antenna with multi-notch band is designed as a circular metallic patch fed by a coplanar waveguide (CPW) loaded with the ERR. To achieve the notched characteristics at desirable frequencies, the multimode ERR is incorporated into the CPW feedline of the planar UWB antenna. The notched frequency band is controlled by dimensions of the ERR structure. The antenna demonstrated a VSWR lower than 2.5:1 and consistent monopole-like, omnidirectional radiation patterns over a 4.8:1 bandwidth. A prototype of the antenna with physical dimensions of 50×50×1.52 mm demonstrates multi-notch characteristic at 3.5, 5.8, and 7.5 GHz in the 2.5 - 12 GHz frequency range