Bidirectional Radiation Pattern Research Articles

Low-profile U-shaped DRA for ultra-wideband applications

In this paper, a microstrip-fed U-shaped dielectric resonator antenna (DRA) is simulated, designed, and fabricated. This antenna, in its simple configuration, operates from 5.45 to 10.8 GHz. To enhance its impedance bandwidth, the ground plane is first modified, which leads to an extended bandwidth from 4 to 10.8 GHz. Then by inserting a rectangular metallic patch inside the U-shaped DRA, the bandwidth is increased more to achieve an operating band from 2.65 to 10.9 GHz. To validate these results, an experimental antenna prototype is fabricated and measured. The obtained measurement results show that the proposed antenna can provide an ultra-wide bandwidth and a symmetric bidirectional radiation patterns. With these features, the proposed antenna is suitable for ultra-wideband applications.

A compact wideband monopole antenna fed by coplanar waveguide

A compact wideband printed antenna fed by coplanar waveguide (CPW) is presented in this paper. The wideband characteristic is achieved by coupling three monopole resonant modes of the proposed antenna. The proposed antenna is built and simulated to verify the design strategy. A wide impedance bandwidth of 100.5% (1.7866-5.3953 GHz) with S11< - 10 dB is achieved. The proposed antenna has stable performance, including bi-directional radiation pattern and gain. It also shows the merits of low cost and simple structure.

Design of a Dual-Band Bidirectional Antenna Using Superellipse-Monopole-Fed Rectangular Ring for IEEE 802.11 a/b/g/n Applications

This paper presents the design of a dual-band bidirectional ring antenna fed by a superellipse surface probe for 2.4/5 GHz WLAN applications. The Method of Moments (MoM) with RWG basis function was utilized in the study and design processes. A prototype antenna was fabricated successfully with the advantages of simple and low-cost structure. The measured impedance bandwidth of 810 MHz (2.10–2.91 GHz) and 2.39 GHz (3.57–5.96 GHz) is achieved for the first and second band, respectively. The peak gains are also feasible, 4.67 dBi at 2.45 GHz and 7.83 dBi at 5.5 GHz, with bidirectional radiation patterns for both bands. From the experimental field tests, the proposed antenna was suitable for most applications in long and narrow communication sites in 2.4/5 GHz bands as desired. Also, the measured and calculated results were in good agreement.

Design of a dual-band indoor antenna with orthogonal bi-directional radiation pattern

Design of a dual-band indoor antenna with orthogonal bi-directional radiation pattern

Wideband DRA Array Placed on Array of Slot Windows

A dielectric resonator antenna (DRA) with ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 35.9 and excited by a printed microstrip line is considered. Such an element achieves 4% matching bandwidth with unidirectional radiation patterns. However, when a rectangular slot is fabricated on the ground plane under the DRA, a 60% bandwidth is achieved with bidirectional radiation patterns. The mutual coupling between two elements is found to be of low level for the entire bandwidth. To improve the front-to-back ratio of the antenna, a reflector made of conducting strips parallel to the antenna polarization is placed behind the slot window. Linear (H- and E-planes) and planar arrays are fabricated and tested achieving good agreement between simulated and measured results providing high confidence on the simulation.

Wideband Circular Polarization Reconfigurable Antenna

This communication introduces a polarization reconfigurable wideband circularly polarized (CP) antenna, which consists of four radiating arms connected to a reconfigurable feeding network. The four radiating arms excited by the feeding network are able to generate wideband CP waves with bidirectional radiation patterns in free space. In order to increase the gain and obtain a broadside radiation pattern, the proposed antenna is placed above a metallic reflector with the distance of quarter wavelength at the center frequency. In addition, polarization reconfigurability is realized by utilizing PIN diodes in the feeding transmission lines such that left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP) modes can be selectively excited by controlling the on / off states of the PIN diodes. The proposed antenna exhibits a wide impedance bandwidth of 80% and an overlapped axial ratio (AR) bandwidth of 23.5% for both modes. The antenna gain is stable across the operating bandwidth with the peak gain of 4.8 dBic. The antenna has a wide AR beamwidth of 90°. The presented work is suitable for GPS, CNSS, or RFID applications.

A small asymmetric coplanar strip fed tri-band antenna for PCS/WiMAX/WLAN applications

In this paper, a small asymmetric coplanar strip (ACS)-fed monopole antenna for tri-band operation is proposed. The proposed antenna is composed of an arc-shaped monopole strip, a rectangular-shaped branch, and an L-shaped strip attached to an extension of the feed line. The three operating bands are obtained from the excitation of resonances due to these strips. The resonances can be controlled by tuning each individual strip separately. The measured results show that the proposed antenna has ź10 dB impedance bandwidth of 250 MHz from 1.75 to 2.0 GHz, 300 MHz from 3.2 to 3.5 GHz and 1.8 GHz from 5.0 to 6.8 GHz. Further, the antenna has good bidirectional radiation patterns in the E-plane, omnidirectional radiation patterns in the H-plane and reasonable peak gains in the all operating bands. With these features and a compact size, the proposed antenna will be suitable for PCS 1900, 3.5/5.5 GHz WiMAX and 5.2/5.8 GHz WLAN portable wireless communication applications.

Strip-coupling circularly polarized antenna and its same-sense bidirectional array

A strip-coupling antenna and its bidirectional array with the same-sense circular polarization are introduced. By placing a bending strip above a narrow slot, circular polarization is obtained by combing the electric and magnetic currents. An array consisting of a three-element long slot and coupled strips on both sides of the slot is then constructed for bidirectional radiations with high gain. The fabricated antenna array shows wide bandwidth of 16.6% (2.16–2.55 GHz) for |S11| < −10 dB and 5.8% (2.33–2.47 GHz) for axial ratio <3 dB. In addition, same-sense bidirectional radiation patterns are also achieved with a high gain over 6.5 dBic.

From optimization to dielectric resonator antenna (DRA) application of YIG: Synthesis approach

The efficacy of yttrium iron garnet (YIG) as magneto-dielectric ceramic, depends heavily on its purity. The presence of undesirable phase(s) such as yttrium iron perovskite (YIP) has led to performance deterioration, which is critical especially in wireless communication devices. This work presents the use of an ANOVA-statistical approach to improve and optimize the YIG’s purity. Effects of particle sizes (5, 50 and 100μm), reactant concentration (excess Fe2O3 in standard YIG formulation – 0, 10, and 20wt%), and formation temperatures (1150, 1200, and 1250°C), on the purity of YIG were investigated. The results indicated that the obtained statistical model adequately represented the experimental data, as reflected in the 3D contour plot. It was also discovered that the concentration of Fe2O3 reactant (up to 8wt%) and formation temperature (1240°C), significantly affects the formation of high-purity YIG while variation of the reactant’s particle sizes is seen insignificant. Finally, a possible application of the optimized YIG (OPYIG) in dielectric resonator antenna (DRA) application is demonstrated. It was found that OPYIG was resonating at 12.50GHz with a stable and bi-directional radiation pattern. This optimization process is successfully produced 99.2% YIG and could be suitable for DRA application.

A compact ACS-fed dual-band monopole antenna for LTE, WLAN/WiMAX and public safety applications

In this paper, a compact asymmetric coplanar strip (ACS)-fed printed monopole antenna for dual frequency operation is presented. The proposed antenna is composed of an ACS-fed monopole structure and two semi circle shaped radiating branches, which occupies a very small size of 13.4 ? 22.7 mm2 including the ground plane. By properly selecting the length and position of these branches, two desired operating bands can be achieved and tuned independently. The simulated and measured return loss results shows that the proposed antenna can be used for long term evolution 2500 (2500---2690 MHz), WLAN 5.2 GHz (5.15---5.35 GHz)/5.8 GHz (5.725---5.825 GHz), WiMAX 5.5 GHz (5.28---5.85 GHz) and 4.9 GHz (4.94---4.99 GHz) public safety applications. The omnidirectional and bidirectional radiation pattern characteristics in H-plane and E-plane of the proposed antenna along with acceptable peak gain make the best suitable candidate for the above intended applications.

Transparent antenna for WiFi application: RSSI and throughput performances at ISM 2.4 GHz

The investigation of the received signal strength indicator (RSSI) and throughput performance in indoor environments for a 2.4 GHz transparent antenna is presented in this paper. The monopole transparent antenna with bi-directional radiation pattern is used in the measurement as the receiver. The RSSI results are taken from a laptop that equipped with AirMagnet wireless PC Card. The antenna throughput is measured with different RSSI levels of the highest, medium and lowest values. Moreover, the measured performance of direct electrical and solar power sources in an indoor environment is compared. The aim is to test the reliability of WiFi systems with solar panel. The measurement results show that throughput performance is proportional to the RSSI values. The RSSI values are between -60 dBm to -90 dBm with average throughput values between 8 and 7 Mbps. Ultimately, it is discovered that the same performance was obtained by using either one of the two power sources. Therefore solar source can be applied to power up the WiFi transparent antenna in real environment that eventually moving towards the green energy and sustainable technology.

Design and compare of Two Coplanar Fed Ultra Wideband Antenna

this paper, design and analysis of two compact coplanar waveguide (CPW) fed ultra wideband (UWB) slot antenna is presented. The proposed antenna consists of a rectangular slot on a ground plane and a triangular patch and another semi- circular patch at the interior portion of the feed that acts as tuning stub of the antenna. The return loss of the developed antenna are measured and compared, which shows that measured result is in good agreement with simulation. It is also seen that the proposed antenna has relatively stable Omni directional radiation pattern in the H plane and bidirectional radiation pattern in the E plane over the frequency range of 3.91 GHz to 10.6 GHz. Keywordsot Antenna, Coplanar Waveguide, Return Loss, Ultra Wideband

Microstrip antenna with complementary split ring resonator loaded ground plane for gain enhancement

ABSTRACTIn this article, microstrip patch antenna with complementary split ring resonator (CSRR) loaded ground plane is proposed for gain improvement. Gain was improved by introducing CSRR slots on the ground plane. The proposed antenna is designed, fabricated, and tested. Measured results are in good agreement with simulation results. The proposed antenna has a size of 40 × 46 × 1.6 mm3. The measured impedance bandwidth is 100 MHz (return loss &lt;−10 dB) from 2.4 to 2.5 GHz, which covers instruments, scientific and measurement (ISM) band applications. Omnidirectional radiation pattern obtained in H‐plane and bidirectional radiation pattern obtained in E‐plane. Parametric study of CSRR was done to obtain best results. The proposed antenna is simple, has good radiation pattern, and very good gain of 5.93 dBi at resonant frequency. Size reduction of 10% was also achieved and bandwidth is slightly greater than unloaded antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:292–296, 2015

Design of Compact Dual-Band/Tri-Band CPW-Fed Monopole Antennas for WLAN/WiMAX Applications

Two compact rupee shaped coplanar waveguide (CPW) fed monopole antennas for WLAN and WiMAX applications are proposed. One of the antennas has a dual band characteristic (measured impedance bandwidth from 2.92---3.7 and 4.6---6.0 GHz) while the other has a triple band characteristic (measured impedance bandwidth from 1.97---2.15, 2.82---3.45 and 4.35---6.0 GHz). Both the proposed antennas measure $$17.5 \times 17.5\times 1.6\,\hbox {mm}^{3}$$17.5×17.5×1.6mm3 in dimensions. The basic radiating element in both the antennas is a rupee shape patch fed by a CPW. The dual frequency band operation is obtained by attaching an additional horizontal L-shape strip. The third frequency band is generated by the introduction of a meander shape strip on one side of the patch. The details of the antenna design along with simulated and experimental results are presented and discussed. The two antennas show nearly omnidirectional radiation patterns in the H-plane and bidirectional radiation patterns in the E-plane with moderate gain in the operating bands. The compact features, simple feeding technique and monopole design make them suitable for portable communication devices.

A tri-port MIMO antenna designed for Micro/Pico Cell applications with self-decoupled structure

A tri-port MIMO antenna designed for Micro/Pico-Cell application is proposed. It is based on printed elements with X-shaped arms, which are oriented to 0°, 120° and 240° in the azimuth plane. The arms of these elements are connected, with which a self-decoupled structure is formed. The mutual coupling between adjacent elements is below −15dB. Meanwhile, it size is compact and bidirectional radiation patterns with around 4dBi Gain and 92° 3dB beam width is achieved, which can provide good pattern diversity and full azimuth coverage in real applications.

Frequency and Pattern Reconfigurable Slot Antenna

A novel frequency and pattern reconfigurable slot antenna is proposed. Slot antenna produces a bidirectional radiation pattern, thus a reflector is positioned behind of the antenna to generate a directional radiation pattern. Two switches are placed in the slot to produce three reconfigurable frequency bands: at 1.82 GHz, 1.93 GHz and 2.10 GHz. The introduction of four slits at the edge of the ground plane offers pattern reconfigurability. To tune the beam angles, three switches are inserted into each slit. By manipulating the phase of upper and lower slits in the ground plane, the proposed antenna is capable of reconfiguring its beam to three different angles at 0°, -15° and +15°. The simulated and measured results of reflection coefficient and radiation patterns are presented and compared.

A Compact Wideband Slot-Loop Hybrid Antenna With a Monopole Feed

This communication presents a compact monopole-fed slot-loop hybrid antenna for wideband wireless communications. The wideband characteristic is achieved by coupling three different resonant modes of the proposed slot-loop hybrid antenna, namely, a loop mode for the lower band, a slot mode for the middle band and a monopole mode for the higher band. The proposed antenna is built and tested to verify the design strategy. The measured impedance bandwidth (|S 11 | <; -10B) ranges from 1.82 GHz to 5.68 GHz (102.9%) with stable performance, including bi-directional radiation pattern, vertical polarization and gain. The proposed slot-loop hybrid antenna also shows the merits of compact dimension, low cross-polarization and low cost.

Broadband circularly polarized printed monopole antenna with unidirectional radiation patterns

ABSTRACTThis article proposes a new broadband circularly polarized (CP) printed monopole antenna (PMA) with unidirectional radiation patterns. The simple structure consists of only a circular patch, a tuning rectangular patch, and an inverted‐L strip protruded from the signal line of a feeding asymmetric coplanar waveguide (CPW). Through simple design procedures, a CP PMA with bidirectional radiation patterns and with a fractional CP bandwidth (CPBW) of larger than 35% can be obtained. By placing an open metal cavity underneath the bidirectional PMA without changing the PMA's structural dimensions, one can obtain unidirectional radiation patterns without downgrading the CPBW. In addition, the peak antenna gain can be raised by about 6 dB. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1535–1540, 2014

4-element planar array antenna for UWB application

A novel low-cost 4-element planar array antenna directly fed by a coaxial cable for Ultra-WideBand (UWB) application is presented. The proposed antenna consists of 2×2 bowtie elements and a simple 1:4 power divider feeding network. Compared to the basic bowtie element, the impedance bandwidth of the array antenna has a significant improvement that the low cut-off frequency is extended from 6 GHz of the bowtie element to 2 GHz. The measured results show that the proposed antenna has a large bandwidth of 2 GHz to 11 GHz for Voltage Standing Wave Ratio (VSWR)<2, and exhibits a bidirectional radiation pattern and a modest gain across the operating band and a peak gain of about 9 dBi at 11 GHz.

A BROADBAND CPW-FED CIRCULARLY POLARIZED SQUARE SLOT ANTENNA FOR UHF RFID APPLICATIONS

A broadband CPW-fed circularly polarized square slot antenna for ultra-high-frequency (UHF) radio frequency identiflcation (RFID) applications is proposed. It consists of a square slot embedded with a spur line along diagonal and an F-shaped feeding structure. The proposed antenna achieves an impedance bandwidth about 307MHz (34.6% @886MHz) and a 3dB axial ratio (AR) bandwidth about 232MHz (24.3% @954MHz). The 3dB AR beam-width is about 96 degrees over the UHF band of 840{960MHz. The proposed reader antenna based on CPW structure is easy to integrate. With the symmetry and bidirectional radiation pattern, there are less readers needed in some applications, such as access control, than the reader with unidirectional pattern, which will deflnitely decrease the implemented cost. Therefore, this universal design with desired performance across the entire UHF RFID band (from 840MHz to 960MHz) can be applied to all the UHF RFID applications worldwide. Detailed considerations of the design and main parameters will be studied in this paper.