S11 Bandwidth Research Articles

A new biopolymer substrate‐based compact monopole antenna covering RFID, WiMAX, and C/X‐band

ABSTRACTA simple design, compact size, multiband monopole antenna comprises of wide arcs and square slots on its radiating element is proposed in this article. After successful completion of the numerical simulation, the proposed antenna has been fabricated with its optimum parameters on 1.0 mm thick 24 × 17 mm2 custom‐made biopolymer substrate with relative dielectric constant εr = 10.0 and loss tangent 0.002. The experimental results obtained from the antenna prototype have been validated with numerical results and they are well matched. The measured data confirms the bandwidth for S11 <−10 dB are of 712 MHz (90.3%), 1.38 GHz (41.3%), 2.46 GHz (30.7%) at 0.788, 3.34, and 8.01 GHz band, respectively. The antenna prototype shows almost symmetrical radiation patterns with maximum measured gain of 1.37, 2.8, and 3.56 dBi for lower, middle, and highest frequency band, respectively. Based on the excellent matching, wide bandwidth, stable radiation, and acceptable gain performance, the compact size monopole antenna finds its potential application in RFID, WiMAX, and C/X‐band applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2002–2005, 2015

A Wideband Rectangular Dielectric Resonator Antenna with Small Ground Plane

A broadband rectangular dielectric resonator antenna with a small ground plane is presented in this article. A U-shaped slot acts as a feeding structure and an effective radiator simultaneously. A parasitic H-shaped slot is adopted to improve the impedance match. The antenna prototype has been fabricated and tested, and good agreement has been observed between the measured and simulated results. A measured bandwidth for S11 <–10 dB of up to 73.72% and a maximum gain of 6.69 dB have been obtained. The total size of the proposed antenna with the ground plane is only ( is the central operating wavelength).

A Planar Monopole Antenna with Wideband Circularly Polarized Characteristic

A new circular polarization planar printed monopole antenna with broadband characteristics in both axial and impedance is proposed and experimentally studied. By inserting a vertical slot into the left ground plane and cutting a horizontal slit in the right ground plane, the impedance bandwidth of the antenna is enlarged, and its wide axial ratio bandwidth is achieved. The measured results show a –10-dB S11 bandwidth of 69.6% from 3.60 to 7.47 GHz and a 3-dB axial ratio bandwidth of 27.9% from 4.72 to 6.25 GHz. The radiations of antenna exhibit a right-hand circular polarization in the +z direction and a left-hand circular polarization in the opposite direction. Moreover, a parametric study of the design is carried out.

A simple design of planar microstrip antenna on composite material substrate for Ku/K band satellite applications

SummaryA straight forward design of rectangular slotted microstrip planar antenna fed by 50 ohm microstrip line is proposed for Ku/K band satellite applications. The radiating patch of the antenna occupies an area of 17 × 17 mm2 and fabricated on 1.0 mm‐thick ceramic filled bioplastic composite material substrate whose dielectric constant (εr) is 10.0. The dual resonant square‐shaped antenna has been formed by inserting four arc shape slots at the corners with the combination of circle and square and wide square shape slot at the center. The results from the measured data show that the antenna has a lower resonant mode impedance bandwidth for S11 &lt; −10 dB is of 18.4% (11.67–14.05 GHz) and upper resonant mode bandwidth is of 8.2% (18.19–19.75 GHz) centered at 12.94 GHz and 19.04 GHz, respectively. The antenna prototype has achieved maximum gains of 3.1 dBi and 4.13 dBi with average radiation efficiencies of 75.3% and 86.4% for the lower band and the upper band, respectively. The numerical data analyses of both the measured and simulated results show relatively good agreement. Moreover, the consistent and symmetrical radiation patters of the proposed antenna make it suitable candidate for the Ku/K band satellite applications. Copyright © 2015 John Wiley &amp; Sons, Ltd.

COMPACT TRIPLE BAND-NOTCHED UWB MIMO ANTENNA WITH SIMPLE STEPPED STUB TO ENHANCE WIDEBAND ISOLATION

In this paper, a very compact ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna, with a high isolation and triple notched bands, is proposed. Its size is dramatically decreased to 30× 26× 0.8mm3 on a cost-effective FR4 substrate. It consists of two rectangular printed monopole (PM) elements and a simple stepped ground stub to enhance wideband isolation. For two different rejected bands of the wireless local area network (WLANs) covering 5.15–5.35 and 5.725– 5.825GHz, four parasitic C-shaped split-ring resonators (PCSRR) are placed on either side of the feed line. By etching two inverted U-shaped slots on the center of the patch, the notched frequency at 4GHz C-band (3.7–4.2 GHz) of satellite communication systems is obtained. The results of simulation and measurement prove a bandwidth of S11 < −10 dB and S12 < −21 dB over the whole band (3.1– 11.2GHz) excluding the three independently adjustable rejection bands. Hence, the proposed UWB MIMO antenna has a very small size, simple structure, higher isolation and three narrower notched bands which effectively save more useful frequencies. Moreover, it is a good candidate for wireless portable UWB MIMO applications.

CPW-FED UWB ANTENNA WITH WIMAX BAND-NOTCHED CHARACTERISTICS

A coplanar wave guide fed (CPW) UWB antenna with provision for rejecting WiMAX band is proposed. The antenna consists of a circular disc which is truncated at the top and a rectangular ground plane with semi-elliptically shaped upper edge. Overall size of the antenna is 25 mm x 20 mm x 1.6 mm. Folded U-slot etched on the radiating patch produces the band rejection characteristics at WiMAX. The S11 (< -10 dB) bandwidth of the antenna varies from 3.1 GHz to greater than 12 GHz with satisfactory band rejection over the range of 3.35 GHz to 3.8 GHz. The extent of pulse distortions due to the antenna is analysed by the antenna transfer functions and group delay measurements. Effects of folded U-slot on the antenna characteristics both in frequency domain and time domain are presented.

A novel CPW-fed wideband printed monopole antenna with DGS

This paper presents a novel printed monopole antenna with defective ground structure for worldwide interoperability for wireless communication. The basic design comprises of a monopole patch with co-planar ground plane which exhibits the impedance bandwidth (S11≤−10dB) of 3.18GHz (from 3.32–6.50GHz) and the peak gain throughout the frequency band is 4.5dB. The initial design is further modified to enhance the impedance bandwidth and gain by employing a defective ground structure in the co-planar ground plane of the monopole patch. The measured bandwidth for return loss S11≤−10dB is 2.44–2.58GHz and 3.5–8.85GHz which cover all the WLAN (2.4/5.2/5.8GHz) bands, WiMAX (2.5/3.5/5.5GHz) bands and point to point (5.925–8.5GHz) high speed wireless applications as per ECC and FCC frequency standards. The experimental and simulated results of a novel CPW-fed (co-planar waveguide) printed monopole antenna with DGS (defective ground structure) are reported here.

Using Thick Substrates and Capacitive Probe Compensation to Enhance the Bandwidth of Traditional CP Patch Antennas

The simplicity and intuitive design of traditional circularly polarized (CP) patch antennas, such as the truncated corner patch antenna, has led to their widespread popularity. However, they are limited to a narrowband performance on the order of 0.1%-2% for simultaneously good S11 and axial ratio (AR). We will prove theoretically that this is a direct result of the probe reactance hindering the use of thicker substrates to increase the bandwidth. Furthermore, we propose a novel compensation technique to enhance the bandwidth capabilities of these CP patch antennas. Our method inserts a capacitive element, such as an annular gap or parallel plate, in series with the probe inductance to remove its effect. We demonstrate this technique with simulations and measurements to obtain AR- S11 bandwidth capabilities as high as 12.6%. To the authors' best knowledge, this is the first time that capacitive compensation and thick substrates have been jointly employed to enable broadband CP patch antennas.

A wideband circularly polarized metallic cavity antenna fed with an L‐shaped probe

ABSTRACTIn this letter, a wideband circularly polarized metallic cavity antenna is designed and fabricated. To enhance both the impedance and axial‐ratio bandwidths (ARBWs), an L‐shaped probe is used to produce two orthogonal TE111 modes for left‐hand circular polarization. The measured impedance bandwidth for S11 ≤ −10 dB and 3‐dB ARBW were 1.72 GHz (20.6%, 7.48–9.2 GHz), and 1.5 GHz (17.3%, 7.9–9.4 GHz), respectively. The measured realized gain at broadside was 6.6–9.3 dBic over the overlapped impedance and AR bandwidth 1.38 GHz (16.1%, 7.9–9.28 GHz). The experimental results reveal that the proposed antenna is attractive for satellite communication applications due to its simple metallic structure, good performance, and strong power‐handling capability. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2398–2403, 2014

Design and Implementation of Low Profile Antenna for Dual-Band Applications Using Rotated E-Shaped Conductor-Backed Plane

A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S 11 < −10 dB is about 1.15 GHz for 5 GHz band and 5.3 GHz for X-band. The measured peak gains are about 1.9 dBi at WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices.

Dual Band MIMO Antenna Composed of Two Low Profile Unbalanced Fed Inverted L Antennas for Wireless Communications

A low profile dual-band multiple-input-multiple-output (MIMO) antenna system is proposed. The proposed MIMO antenna consists of two low profile unbalanced fed inverted L antennas with parasitic elements to resonate at 2.45 GHz and 5 GHz. The structure is uncomplicated by locating two ultra low profile inverted L antennas on the finite conducting plane. The proposed MIMO antenna is numerically and experimentally analyzed. When the size of conducting plane is 55 mm by 55 mm and the height of antenna is 9 mm, the directive gain of 4.11 dBi and the S11 bandwidth of 5.71% are achieved for lower frequency of 2.45 GHz. At the upper frequency of 5 GHz, the directive gain of 8.22 dBi and the S11 bandwidth of 6% are obtained. The proposed antenna has good diversity gain, shown by the correlation coefficient becomes less than 0.005 at the frequency of 2.45 GHz and 5 GHz band when the distance between inverted L elements is 41 mm. A good agreement between calculated and measured results is obtained. The results show that the weak mutual coupling of the proposed antenna and this feature enables it to cover the required bandwidths for WLAN operation at the 2.4 GHz band and 5 GHz band.

Design of an ultrawideband conformal metal antenna

ABSTRACTIn this article, a novel design of volcano smoke antenna is proposed as an ultrawideband (UWB) conformal antenna. The radiating element and CPW feed line are in the same plane that makes the antenna completely planar. The proposed planar metal antenna is bent on a cylindrical surface, and the characteristics of the antenna for different bent conditions are studied. This study shows no significant change of reflection coefficient and radiation pattern characteristics of the bent antenna compared to that of flat position. The impedance bandwidth for S11 &lt; −10 dB of the bent antenna covers the UWB (3.1–10.6 GHz). Variation of absolute gain and group delay of the antenna under flat and bent conditions are shown in this article. The measured reflection coefficient agrees with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:430–434, 2014

Asymmetric slotted antenna for circular polarisation and WiMAX applications

An asymmetric slotted antenna for circular polarisation and WiMAX applications is proposed in this letter. The single-layer antenna is composed of a rectangular ground plane embedded with two equal-sized circular slots. The circular polarisation radiation characteristics are achieved by proper asymmetry circular slots. A cup-shaped metallic strip extends current route to make the fundamental resonant mode shift to lower frequency band and improve the matching at high band. The overall dimension of the antenna comes 70 mm × 60 mm × 1.5 mm, which is printed on an FR4 substrate with a dielectric constant of 4.3. Experimental results show that the proposed antenna achieved 10-dB S11 bandwidth from 1.07 to 6.79 GHz and the obtained 3-dB axial ratio bandwidth can reach as large as 44.8% with a peak gain of 4.4 dBi.

Design of Compact CPW‐FED Monopole Antenna for WLAN/WiMAX Applications Using a Pair of F‐Shaped Slits on the Patch

ABSTRACTIn this article, a compact and small coplanar waveguide fed (CPW‐fed) monopole antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. In the proposed antenna, the main target is to present a compact structure with a step‐by‐step design procedure on the patch. The antenna consists of a slotted rectangular patch as radiator, a partial CPW‐ground plane. To excite WiMAX/WLAN bands, two F‐shaped slits are inserted into the rectangular patch that resonates at the frequencies of 3.5 and 5.4 GHz. By suitable adjusting the lengths of the F‐shaped design, much wider impedance bandwidth can be produced, especially at the lower band of WLAN/WiMAX. The size of the antenna is 15 × 15 × 1.6 mm3. A prototype of the designed antenna is constructed and experimentally investigated. The −10 dB S11 bandwidths of them are (3.15–4.63 GHz) and (4.75–6.62 GHz), respectively, which can cover both the WLAN bands (5.15–5.35 GHz and 5.725–5.825 GHz) and the WiMAX bands (3.4–3.6 GHz and 5.25–5.85 GHz). Proper omnidirectional radiation pattern characteristics and enough gains are obtained over the operating bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2337–2340, 2013

Broadband CPW-fed circularly polarized antenna with machine-gun-shaped feeding line and symmetric-aperture

This paper presents a new design for wide slot circularly polarized (CP) antenna (WSCPA). Compared with existing WSCPA, the proposed design possesses much wider return loss S11 bandwidths and CP bandwidths. The main features of the antenna structure include a machine-gun-shaped CPW feeding line and a wide symmetric-aperture along the diagonal axis. Wideband return loss and CP radiations have been achieved by properly tuning circular-shaped aperture and feeding line. The measured bandwidths of 10 dB return loss and 3 dB axial ratio (AR) are around 110.2% (2.2-7.6 GHz) and 105.9% (2- 6.5 GHz), respectively. Throughout this letter, the improvement process of the AR and S11 properties is completely presented and discussed.

Design and Simulation of a PIFA Antenna for the Use in 4G Mobile Telecommunications Networks

This paper describes the design and simulation by HFSS simulator of a probe-fed and multi-band Planar Inverted-F Antenna (PIFA) for the 4G mobile networks. The antenna works in 8 bands. Five bands are auctioned by FCC for 4G (LTE and WiMax) such 710 MHz, 1900 MHz (PCS), 2.3 GHz (WCS band), 3.65 GHz (rural 4G) and 5.8 GHz (FCC unlicensed band). The antenna allows working around 910 MHz ISM band. The GPS signal can be received in GPS L2 band around the frequency 1575 MHz. The antenna offers also a wideband around 8.62 GHz. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameters, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect mostly the requirements.

Design and Simulation by HFSS of a Slim UWB PIFA Antenna

This paper describes the design and simulation by High Frequency Structure Simulator (HFSS) of a probe-fed Planar Inverted-F Antenna (PIFA) for the Ultra Wide Band (UWB) personal area networks. The slim antenna presents a height of 2 mm and a bandwidth of more than 766 MHz. This bandwidth was improved by etching a U-slot in the antenna patch. The bandwidth offered then by the antenna is 839 MHz around the resonant frequency of 9 GHz. The improvement of bandwidth was accompanied by decreasing in gain and radiation efficiency. The simulation allowed the characterization of the designed antenna and the computing of different antenna parameters like S11 parameter, resonant frequency, bandwidth, radiation efficiency, gain and diagram pattern. The results are very interesting and respect the Federal Communications Commission (FCC) requirements.

Broadband Circularly Polarized Printed Slot-Monopole Antenna

A slot and a monopole antenna fabricated on a single substrate can generate circularly polarized radiation over a broad band of frequencies. Appropriate power division network is used to feed the elements from a microstrip transmission line. Radiation pattern of antenna is circularly polarized in the broadside direction. Measured 3-dB axial-ratio (AR) bandwidth is 30%, and the 10-dB S11 bandwidth is 51%.

Differential Microstrip and Slot-Ring Antennas for Millimeter-Wave Silicon Systems

Differential on-chip microstrip and slot-ring antennas with a quartz superstrate are presented for wafer-scale silicon systems. The antennas are fed at the nonradiating edge, which is compatible with differential coupled-lines, and are built on a 0.13-μ m CMOS process with a layout that meets all the metal density rules. A high radiation efficiency is achieved using a 100- μm quartz superstrate placed on top of the silicon chip. Both antennas have a measured gain varies from about 2 to 3 dBi at 91-94 GHz, with a - 10-dB S11 bandwidth of 7-8 GHz and a simulated radiation efficiency of >;50%. The designs are compatible with single- and multielement transceivers, and with wafer-scale imaging systems and power-combining arrays.

Qualification of Polyimide Based Coverlays for 900 MHz and 2.40 GHz Microstrip Antenna Applications

Organic coverlays are required to protect microstrip circuits in most applications. The presence of coverlay can potentially influence the performance of microstrip antennas. This paper describes the qualification of polyimide based coverlays for microstrip antennas both in 900 MHz and 2.50 GHz frequency bands. An Inverted F-shaped antenna fabricated on FR-4 dielectric is used as the test vehicle and two different coverlay materials are tested with respect to key parameters like resonant frequency, S11 bandwidth, antenna gain, frequency detuning, and radiation pattern. The data presented in this paper clearly indicates polyimide materials are well suited to cover microstrip antenna circuits with minimal impact on performance.