Compact frequency reconfigurable triple band notched monopole antenna for ultrawideband applications

A compact ultra‐wideband (UWB) reconfigurable microstrip fed monopole antenna having size of 0.22 λ₀ × 0.28 λ₀ × 0.005 λ₀ with switchable frequency bands is presented. Triple band notched characteristics are achieved by inserting two stubs at top of radiator and one slot in between the radiator and microstrip feed line. Proposed antenna achieves reconfigurability with three PIN diodes at strategic positions to obtain eight different operational modes. In one of the operational modes, antenna operates in the entire UWB (3‐14 GHz) with fractional bandwidth of 127.5%. Two stubs are used to notch two frequency bands worldwide interoperability for microwave access (3.3‐3.6 GHz/WiMAX) and C‐band (3.7‐4.2 GHz). T‐shaped slot is also inserted to notch wireless local area network (5.725‐5.825 GHz/WLAN) frequency band. Proper biasing of PIN diodes is done by using suitable chip inductors and capacitors. Proposed antenna exhibits stable radiation patterns with average gain of around 3 dBi. Simulation and measurement results are in good agreement. Proposed antenna is suitable for on‐demand band rejection of parasitic bands coexisting in UWB.     

Compact triple‐band stacked monopole antenna for USB dongle applications

In this article, a novel compact triple‐band stacked monopole antenna for USB dongle applications is proposed. The antenna consists of an e‐shaped monopole connected directly to the feedline and a square patch‐shaped monopole at another layer connected to feedline by a metallic pin. The e‐shaped monopole is used to obtain WLAN band (2.4‐2.48 GHz) and WiMAX band (3.4‐3.69 GHz). On the other hand, square patch‐shaped monopole is introduced to get WLAN bands (5.15‐5.35 and 5.725‐5.825 GHz) and WiMAX band (5.25‐5.85 GHz). The antenna is compact with the dimension of 17 × 13 mm².     

A band‐suppression UWB suspended planar antenna incorporating a slotted spiral resonator

A novel miniaturized planar inverted F‐L antenna assembly is considered for UWB radio operations. The antenna design utilizes the electromagnetic coupling between an air dielectric planar inverted‐F antenna (PIFA) and a parasitic planar inverted‐L (PIL) element, with broadband feeding from a rectangular plate. To improve the functionality of the channel, a simple notch filter has been introduced through a local modification to the broadband feed plate, this takes the form of a simple slotted rectangular spiral resonator which is etched directly onto the plate. This allows the proposed antenna to maintain its full band UWB coverage, with the HYPERLAN/2 band centered at 5.35 GHz to be effectively rejected over the sub‐band 5.15–5.725 GHz, without the need for substantial re‐optimization of its principal structure parameters. The impedance bandwidth operates over the full UWB band, with VSWR better than 2, this performance is not degraded by the presence of the band rejection. The observed gains, radiation patterns, and group delay confirm that the antenna has appropriate characteristics for short range wireless applications. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Quad notch UWB antenna using combination of slots and split‐ring resonator

A novel coplanar waveguide fed UWB antenna with quad notch band characteristics has been proposed in this work. The antenna layout is designed based on a combination of well‐known geometrical shapes: a half ellipse patch, rectangle, and triangle. The shape of the ground plane is partially tapered rectangular. The overall dimension of the antenna is 41.5 × 32 mm. The antenna uses three U‐shaped slots at the top surface to create three notched band characteristics. A split‐ring resonator is then introduced at the bottom surface of the antenna. With the integration of split‐ring resonator at the bottom surface, an additional notch band at 7.25 to 7.75 (6.7%) GHz is created in the antenna. The designed antenna has an operating impedance bandwidth (VSWR ≤2) ranges from 3.03 to 12.34 GHz except in quad frequency stop bands of 3.3 to 3.7 (11.4%), 5.15 to 5.35 (3.8%), 5.725 to 5.825 (1.7%), and 7.25 to 7.75 (6.7%) GHz. The proposed antennas are successfully designed, prototyped, and measured. The simulated and measured results are extensively studied and discussed. Correlation between the time‐domain transmitting antenna input signal and the received antenna output signal is calculated in order to ensure that the proposed antenna can be used in pulse‐communication systems. This antenna finds applications in medical imaging, military radar systems, and other common UWB applications.     

Design of a microstrip fed printed monopole antenna for bluetooth and UWB applications with WLAN notch band characteristics

In this article, a microstrip fed printed dual band antenna for Bluetooth (2.4–2.484 GHz) and ultra‐wide band (UWB; 3.1–10.6 GHz) applications with wireless local area network (WLAN; 5.15–5.825 GHZ) band‐notch characteristics is proposed. The desired dual band characteristic is obtained by using a spanner shape monopole with rectangular strip radiating patch, whereas the band‐notch characteristics is created by a mushroom‐like structure. The Bluetooth and notch bands can easily be controlled by the geometric parameters of the rectangular strip and mushroom structure, respectively. The proposed antenna has been designed, fabricated, and tested. It is found that the proposed antenna yields both the Bluetooth and UWB performance in the frequency regions of 2.438 to 2.495 GHz and 3.10 to 10.66 GHz, respectively for |S₁₁| ≤ ?10 dB with an excellent rejection band of 5.14 to 5.823 GHz to prevent WLAN signals. The experimental results provide good agreement with simulated ones. Surface current distributions are used to analyze the effects of the rectangular strip and mushroom. The designed antenna exhibits nearly omnidirectional radiation patterns, stable gain along with almost constant group delay over the desired bands. Hence, the proposed antenna is expected to be suitable for both Bluetooth and UWB applications removing the WLAN band. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:66–74, 2015.     

A triple‐band antenna for MIMO WLAN applications

A novel triple‐band antenna element by etching parasitic slot on ground plane is presented. A three‐element antenna system for WLAN MIMO communications is fabricated by using the proposed antenna element. The triple‐band antenna element is designed for the WLAN standard frequency ranges (2.4‐2.485, 5.15‐5.35, and 5.475‐5.725 GHz). The three identical antenna elements are rotationally symmetric on the substrate, isolated by using metal‐vias cavity. The measured average peak gain within the operational bandwidth is about 2.7 dBi. The isolation between the antenna elements can achieve better than 17 dB at the lower band (2.25‐2.65 GHz), while more than 32 dB at the higher bands (5.20‐5.35 and 5.47‐5.73 GHz) is obtained.     

Design and development of enhanced bandwidth multi‐frequency slotted antenna for 4G‐LTE/WiMAX/WLAN and S/C/X‐band applications

A multi‐frequency rectangular slot antenna for 4G‐LTE/WiMAX/WLAN and S/C/X‐bands applications is presented. The proposed antenna is comprised of rectangular slot, a pair of E‐shaped stubs, and an inverted T‐shaped stub and excited using staircase feed line. These employed structures help to achieve multiband resonance at four different frequency bands. The proposed multiband slot antenna is simulated, fabricated and tested experimentally. The experimental results show that the antenna resonates at 2.24, 4.2, 5.25, and 9.3 GHz with impedance bandwidth of 640 MHz (2.17‐2.82 GHz) covering WiMAX (802.16e), Space to Earth communications, 4G‐LTE, IEEE 802.11b/g WLAN systems defined for S‐band applications. Also the proposed antenna exhibits bandwidth of 280 MHz (4.1‐4.38 GHz) for Aeronautical and Radio navigation applications, 80 MHz (4.2‐4.28 GHz) for uncoordinated indoor systems,1060 MHz (5.04‐6.1 GHz) for the IEEE 802.11a WLAN system defined for C‐band applications and 2380 MHz (7.9‐10.28 GHz) defined for X‐band applications. Further, the radiation patterns for the designed antenna are measured in anechoic chamber and are found to agree well with simulated results.     

A compact dual‐band zeroth‐order resonator antenna loaded with meander line inductor

A novel zeroth‐order resonator (ZOR) meta‐material (MTM) antenna with dual‐band is suggested using compound right/left handed transmission line as MTM. In this article, suggested antenna consists of patch through series gap, two meander line inductors, and two circular stubs. The MTM antenna is compact in size which shows dual‐band properties with first band centered at 2.47 GHz (2.05‐2.89 GHz) and second band is centered at 5.9 GHz (3.70‐8.10 GHz) with impedance bandwidth of (S₁₁ < ? 10 dB) 34.69% and 72.45%, respectively. At ZOR mode (2.35 GHz), the suggested antenna has overall dimension of 0.197λ_o × 0.07λ_o × 0.011λ_o with gain of 1.65 dB for ZOR band and 3.35 dB for first positive order resonator band which covers the applications like Bluetooth (2.4 GHZ), TV/Radio/Data (3.700‐6.425 GHz), WLAN (5‐5.16 GHz), C band frequencies (5.15‐5.35, 5.47‐5.725, or 5.725‐5.875 GHz) and satellite communication (7.25‐7.9 GHz). The radiation patterns of suggested structure are steady during the operating band for which sample antenna has been fabricated and confirmed experimentally. It exhibits novel omnidirectional radiation characteristics in phi = 0° plane with lower cross‐polarization values.     

Implementation of hybrid fractal metamaterial inspired frequency band reconfigurable multiband antenna for wireless applications

In the present paper authors propose the design and analysis of a hepta band metamaterial inspired octagonal shape antenna using hybrid fractals for wireless applications. Multiband characteristics in the designed antenna is accomplished by introducing of slotted octagonal shape radiating part with hybrid fractal form of Moore curve and Koch curve and two SRR cells. The frequency band reconfigurability is obtained with aid of PIN diodes placed inside the strips connected between Moore curve (fused with centered Koch curve) and feedline. During ON mode of PIN diode antenna operates at seven microwave frequency S‐band WiMAX (3.4~3.69 GHz—IEEE 802.16e)/Lower C‐band terrestrial fixed and mobile broadband application (4.25~4.76 GHz)/C‐band WLAN (5.15~5.35/5.75~5.825 GHz—IEEE 802.11a] (5.4~5.9 GHz)/Lower X‐band Earth exploration‐satellite service ITU region 2 (7.9~8.4 GHz)/Upper X‐band Amateur satellite operating band (10.45~10.50 GHz)/Lower Ku‐band Radar communication application (13.25~13.75 GHz)/Middle Ku‐band Geostationary satellite service (14.2~14.5 GHz) covering various wireless applications. Proposed design exhibit hexa/hepta band features during OFF/ON mode of PIN diode. An acceptable gain, stable radiation characteristics, and good impedance matching are observed at all the resonant frequencies of the proposed structure.     

A compact printed ultra‐wideband multiple‐input multiple‐output prototype with band‐notch ability for WiMAX,LTEband43, and WLAN systems

A compact ultra‐wideband multiple‐input multiple‐output (UWB‐MIMO) antenna with good isolation and multiple band‐notch abilities is developed in this work. It consists of two quadrant shaped monopole antennas backed by ground stubs. A good isolation is achieved due to the two proposed extended curved ground stubs. The frequency rejection for the WLAN system is realized by loading a capacitive loaded loop resonator adjacent to the feed line. The band rejection for the WiMAX and LTE band43 system is achieved by embedding a quadrant shaped CSRR on each radiator's surface. The measured bandwidth of the antenna is 3.06 GHz‐11 GHz (|S₁₁| < ?10 dB and |S₂₁| < ?18 dB) with a band rejection from 3.5 GHz‐4 GHz to 5.1 GHz‐5.85 GHz, respectively. Time domain performances are investigated in terms of group and phase delay characteristics. Diversity characteristics are evaluated in terms of the envelope correlation coefficient, mean effective gain, and channel capacity loss.     

Three‐dimensional printed wideband,dual‐cavity Ku‐band antenna

A novel three‐dimensional (3D) printed, wideband, and low cost bull's eye antenna is proposed and designed for Ku‐band applications. The proposed antenna covers entire Ku‐band satellite communication bands starting from 10.5 GHz to 14.5 GHz. The antenna structure consists of dual‐cavity radiating aperture surrounded by a circular groove. With the addition of cavity and corrugation, the antenna gain is increased more than 6 dB. The antenna is fabricated using 3D printing technology and conductive painting. Measurement results indicate that the antenna has 72% fractional bandwidth from 8 GHz to 17 GHz. Measured antenna peak gain is 13.5 dBi at 13 GHz and no less than 11.5 dBi throughout the entire Ku band.     

Additively manufactured trapezoidal grooves for wideband and high gain Ku‐band antenna

Grooves around aperture antennas are known to be instrumental in obtaining directive antenna patterns. The shapes of the grooves are often restricted to rectangular or triangular due to manufacturing difficulties in traditional metal machining, and because of this reason, the effect of groove shape on antenna performance is often overlooked. The aim of this study is to analyze different groove shapes with the help of additive manufacturing. Waveguide slot fed, dual cavity aperture antenna with grooves is designed and the effect of groove shapes on antenna performance is studied at Ku band. Two antennas with and without grooves are built using 3D printing technology. Measured antenna performance reveals 5 GHz bandwidth covering 10 to 15 GHz for Ku‐band satellite communications and part of the X‐band applications. Proposed antenna achieves 13.25 dBi peak gain at 14 GHz and the gain is better than 11.25 dBi over the entire Ku‐band uplink and downlink frequency bands.     

Compact ultra‐wideband slot antenna with three notched‐band characteristics

A very compact ultra‐wideband (UWB) slot antenna with three L‐shaped slots for notched‐band characteristics is presented in this article. The antenna is designed and fabricated using a new stepped slot with different size, integrated in the ground plane, and excited by a 50 Ω microstrip transmission line. The stepped slot is used to minimize the dimensions of the antenna and to achieve an impedance bandwidth between 2.65 and 11.05 GHz with voltage standing wave ratio (VSWR) less than 2. The length of the stepped slot is equal to a quarter wavelength to create a resonance in the desired frequency. Three L‐shaped slots with various sizes are etched in the ground plane to reject three frequency bands in C‐band (3.7‐4.2 GHz), WLAN (5.15‐5.825 GHz), and X‐band (7.25‐7.75 GHz), respectively. The notched‐band frequency can be controlled by changing the length of the L‐shaped slot. The proposed antenna has a very small size (20.25 × 8 × 1.27 mm³) compared with previous works. The measured and simulated results show a good agreement in terms of radiation pattern and impedance matching.     

Enhancement of gain with corrugated Y‐shaped patch antenna for triple‐band applications

In this article, investigation has been carried out on Y‐shaped patch antenna to produce triple‐band for wireless applications. The corrugated Y‐shaped patch antenna is considered to produce low reflection coefficient with high gain at the triple‐bands. The corrugated Y‐shaped patch antenna is resonates at 4.19 GHz (4‐4.43 GHz), 8.79 GHz (8.61‐9.01 GHz), 13 GHz (12.6‐13.6 GHz) frequencies with reflection coefficient of ?29.26 dB, ?34.87 dB, ?40.37 dB and gain 5.01 dBi, 5.42 dBi, 7.46 dBi, respectively. The proposed corrugated Y‐shaped patch antenna works three frequency bands at radio communications, satellite communications, and aeronautical radio navigation applications, respectively.     

A vertex‐fed hexa‐band frequency reconfigurable antenna for wireless applications

Present article embodies the design and analysis of an octagonal shaped split ring resonator based multiband antenna fed at vertex for wireless applications with frequency‐band reconfigurable characteristics. The proposed antenna is printed on FR4 substrate with electrical dimension of 0.4884 λ × 0.4329 λ × 0.0178 λ (44 × 39 × 1.6 mm³), at lower frequency of 3.33 GHz. The antenna consists of SRR based vertex fed octagonal ring as the radiation element and switchable reclined L‐shaped slotted ground plane. Antenna achieves six bands for wireless standards viz: upper WLAN (5.0/5.8 GHz), lower WiMAX (3.3 GHz), super extended C‐band (6.6 GHz), middle X band (9.9 GHz—for space communication), and lower K_U band (15.9 GHz—for satellite communication systems operating band). Stable radiation patterns are observed for the operating bands with low cross polarization. The proposed design achieves hexa band characteristics during switching ON state of PIN diode located at reclined L‐shaped slot in the ground plane. Experimental characteristic of antenna shows close agreement with those obtained by simulation of the proposed antenna.     

Development of “H‐Shaped” monopole antenna for IEEE 802.11a and HIPERLAN 2 applications in the laptop computer

A very low profile and ultra‐thin “H‐Shaped” antenna for IEEE 802.11a and HIPERLAN 2 wireless applications in the laptop computer is developed. The antenna is designed using only a pure copper strip of size 17.5(L) × 4(W) mm² with thickness of only 0.035 mm. The novelty of the proposed antenna is that the antenna is designed with only one rectangular radiating strip without using any additional reactive components, vias or three dimensional structure. Furthermore, the proposed antenna does not require any additional ground plane for installing in laptops. The proposed antenna is comprised of one radiating strip, one rectangular stub, and two resonating slots, namely, “X” and “Y” of length 7.5 mm and 7 mm, respectively. The proposed structure resonates at around 5.5 GHz can cover the (5.15‐5.35/5.725‐5.825) GHz IEEE 802.11a and (5.15‐5.35/5.470‐5.725/5.725‐5.925) GHz HIPERLAN 2 bands. The fabricated prototype antenna has measured impedance bandwidth (VSWR<2) of 15% (5.10‐5.92 GHz) across the operating bands. The measured radiation patterns are nearly omnidirectional along with stable gain of 5 dBi. Moreover, the proposed antenna exhibits excellent radiation efficiency of around 90% across the operating bands. The simulated and measured results of antenna are found to be in good agreement. The very low profile and ultra‐thin structure make it an excellent candidate for wireless operations in the ultra‐thin laptop computers.     

Dielectric resonator array antenna for triple band WLAN applications with enhanced gain

An H‐shaped dielectric resonator array antenna is presented for wideband applications. The proposed antenna is excited by slot feed mechanism and investigated experimentally. The antenna covers the frequency ranges from 1.41 to 2.59 GHz, and 4.73 to 6.06 GHz with the corresponding impedance bandwidth of 59% and 24.65%, respectively. The simulation results fulfill the bandwidth requirements of IEEE 802.11a/b/g (2.4‐2.484 GHz/5.15‐5.35 GHz/5.725‐5.825 GHz) for Wireless local area network (WLAN) applications. The proposed antenna has simple structure, easy to fabricate and its measured radiation pattern shows a reliable performance in the desired operating bands.     

A low‐profile dual port UWB‐MIMO/diversity antenna with band rejection ability

A band notched ultra‐wideband (UWB) antenna is presented in this article as a good prospect for multiple‐input multiple‐output (MIMO)/diversity application. The proposed MIMO antenna is constituted of two modified rectangle‐shaped patch antenna elements. A stepped stub is extended from the modified ground plane as a decoupling element between the radiators to realize a good isolation level between them. A band rejection response is obtained by connecting an open resonant stub to each of the radiators. The simulated prototype is fabricated and tested for verification. Results reveal that the proposed prototype provides a 10 dB return loss bandwidth from 3.08 to 10.98 GHz with band notch characteristics from 4.98 to 5.96 GHz, and a good port isolation level (S₂₁ ≤ 20). Diversity performances are ensured in terms of total active reflection coefficient, envelope correlation coefficient (<0.013 except notch band), diversity gain (≈9.51 dB), mean effective gain ratio (≈1), and channel capacity loss (≤0.35 bps/HZ except notch band). It evidences that the presented band notched UWB antenna can be a good prospective for MIMO/diversity applications.     

A compact uniplanar antenna for nine‐band LTE/WWAN operation in tablet computers

A compact uniplanar dual wideband antenna for tablet computers is presented. The proposed antenna provides full coverage of LTE700/2300/2500, GSM850/900/1800/1900, UMTS2100, Bluetooth, and 2.4‐GHz WLAN bands with a very small foot print 30 × 10 mm². The antenna has uniplanar structure and is easy to fabricate on single side of 0.8‐mm thick FR4 substrate. This is achieved through three optimized strips: a feeding strip, an inductively coupled inverted L‐shaped strip, and a shorted strip embedded with SMT components. The proposed design supports more than eight operating bands in 3:1 VSWR standard, exhibiting positive gains over all nine bands of operation and 80%–90% radiation efficiency in the higher LTE and WWAN bands. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:496–502, 2016.