362 research outputs found
A New Wideband Circularly Polarized Dielectric Resonator Antenna
A wideband and compact circularly polarized (CP) C-shaped dielectric resonator antenna (DRA) is presented. The proposed C-shaped DR is excited by a simple stripe line connected to a coplanar waveguide (CPW) feeding line. The C-shaped DRA is circularly polarized with 19% axial ratio (AR) bandwidth. It is found that the CP bandwidth can be expanded by using a narrow short circuit strip. The final design achieves CP with 50% AR bandwidth. The proposed circularly polarized DRA (CPDRA) with good radiation characteristics offers an impedance bandwidth of 58% between 3.45 and 6.26 GHz for VSWR ≤ 2. The proposed DRA is fabricated and tested. Very good agreement between simulated and measured results is obtained
Vegetation attenuation measurements and modeling in plantations for wireless sensor network planning
Wideband jean antenna with bending structure for microwave imaging applications
In this paper, a wideband jean antenna with bending structure for flexible microwave imaging applications is presented. Coplanar waveguide (CPW) feeding structure with Koch shape ground slotted technique has been implemented for widening the bandwidth. The design evolution process of the proposed antenna is started from a simple CPW-fed monopole antenna to bending circumstance. The proposed antennas under normal condition, bending circumstance and as well as on-arm bending effect are simulated and optimized using CST microwave studio software and fabricated; also tested so as to validate the results. Under normal condition, the antenna provides measured bandwidth of 4500 MHz (1.5-6 GHz) in the case of |S11|≤−10 dB while 4360 MHz (1.44-5.8 GHz) for the measured bandwidth under bending circumstance is obtained. Also, there is a slight degradation on the reflection coefficient of the antenna under on-arm bending so that measured bandwidth became narrower with operating frequency of 3800 MHz (2.2-6 GHz). The measured gain of the antenna fluctuates between 2.5-5.6 dBi and 1.5-2.8 dBi with quasi-omnidirectional pattern within the expected frequency band for normal and bending condition, respectively. The proposed antenna provides a good performance in terms of its reflection coefficient and radiation characteristics. Therefore, due to insensitiveness to bending and body effect, the proposed antenna has become good candidate for microwave imaging applications
Mutual coupling reduction and pattern error correction in a 5G beamforming linear array using CSRR
A four-element printed antenna array operating at 25 GHz frequency with complementary split ring resonator.
(CSRR) has been proposed for beamforming applications. The CSRR elements has been used to suppress the mutual coupling in the proposed array. The existence of the CSRR configuration in antenna array, controls the unnecessary surface current flow between the array elements, thus the mutual coupling between array elements has been significantly reduced up to -55 dB. The effect of mutual coupling on the array radiation patterns has been studied in the presence and absence of CSRRs. The effectiveness of CSRR has been studied by steering the main beam as well as the nulls in different angles. By implementing the CSRR elements in array antenna, the distorted array patterns have been recovered and are presented. The proposed antenna array with the CSRR has the advantage of easy and low-cost fabrication and it offers excellent coupling suppression without changing the antenna profile. The commercially available simulation tools such as Matlab and Ansys HFSS have been used for array weights calculation and antenna design respectively. Finally, the fabricated prototype has been experimentally verified, and it shows that the analytical and computed results agree well with the measured results
Dual band rectangular dielectric resonator antenna for WLAN application
A compact dual band ring shape rectangular dielectric resonator antenna (RRDRA) to operate at 2.4 GHz and 5 GHZ WLAN application is proposed. In this design the dielectric resonator is fed by modified 50Ω trapezoidal micro strip line situated on top of the FR4 substrate. The simulated and measured impedance bandwidth achieved at 2.4 GHZ is 12.42% (2.3149-2.6132) and 12.9% (2.21-2.52) respectively; whilst for 5 GHZ at 13% (5.1795-5.8914) and 13.2% (5.08-5.81) for S11<-10 dB. And the gain of the proposed antenna is 4.9dBi and 5.9 dBi at 2.4 GHz 5GHZ respectively. Results are simulated using Ansoft High frequency structural simulator (HFSS) for the study of impedance bandwidth, return loss, radiation pattern and antenna gain. Furthermore the antenna has been fabricated and tested. The measured characteristics of the proposed antenna are in good agreement with the simulated results
Low sidelobe and wideband characteristics of density tapered arrays for 5G mobile systems
Conventional mobile base station antennas are composed of equally spaced linear array antennas. In order to achieve low side lobe characteristics, excitation coefficients for array elements are determined by a feeding network. Because of complexity of the feeding network, applicable frequency range is limited. In 5G mobile system, multi frequency band operation is requested. For achieving low sidelobe and wide frequency characteristics, a density tapered array configuration is promising. Because of uniform excitation coefficients, feed network has no frequency dependence and wide frequency range application is expected. In this paper, abilities and design method of low sidelobe characteristics are investigated. By density tapering, sidelobe levels are reduced from-13dB to -16dB. As for wide band characteristics, low sidelobe characteristics are maintained during 28GHz to 56GHz operations. Usefulness of a density tapered array is numerically clarified
Broadband Resonant Elements for 5G Reflectarray Antenna Design
The performance investigation of two novel resonant elements is presented in this work for 5G reflectarray antenna design. Two dual resonance elements with wide reflection phase range have been developed from a square patch element by a novel corner bending tactic. The reflection loss and reflection phase range performance of the proposed elements have been compared with conventional square patch element at 26 GHz. The results have shown a reflection phase swing of 629° and 632° for Bent Width and Bent Length elements respectively. The broadband features of proposed elements can radically improve the bandwidth performance of a reflectarray antenna
A review of wideband reflectarray antennas for 5G communication systems
The advancement in the current communication
technology makes it incumbent to analyze the conventional
features of reflectarray antenna for future adaptability. This
work thoroughly reviews the design and experimental features
of reflectarray antenna for its bandwidth improvement in microwave
and millimeter wave frequency ranges. The paper
surveys the fundamental and advanced topologies of reflectarray
design implementations which are needed particularly for its
broadband features. The realization of its design approaches
has been studied at unit cell and full reflectarray levels for
its bandwidth enhancement. Various design configurations have
also been critically analyzed for the compatibility with the high
frequency 5G systems
Mutual Coupling Reduction between Asymmetric Reflectarray Resonant Elements
A physically asymmetric reflectarray element has been proposed for wide band operations. The dual resonant response has been introduced by tilting one side of the square path element. The numerical results have been analyzed in the frequency band between 24GHz to 28GHz where a reflection phase range of more than 600° has been achieved. The proposed asymmetric element can produce mutual coupling with adjacent elements on a reflectarray. This effect has been monitored by placing the elements in a mirror configuration on the surface of reflectarray. The single unit cell element results have been compared with conventional 4 element unit cell and proposed mirroring element configuration. The proposed mirroring element technique can be used to design a broadband reflectarray for high gain applications
Higher-order mode rectangular dielectric resonator antenna for 5G applications
The excitation of the higher-order mode, TEy 1δ3 in rectangular dielectric resonator designed was explored to enhance the antenna gain and detailed elaboration is presented in this paper. The antenna was fed by a 50Ω microstrip line through an aperture cut in the ground plane. Besides avoiding spurious radiation, this feeding technique gives flexibility in controlling the amount of coupling in order to reduce the Q-factor in the higher-order mode RDRA. A design was developed and subsequently simulated using Ansoft HFSS ver 16.0 by utilizing Duroid 5880 dielectric substrate with a thickness (ts) of 0.254 mm, a permittivity (εs) of 2.2 and a loss tangent (δ) of 0.001 at 15 GHz. The higher-order mode, TEy 1δ3 RDRA achieved the measured gain at 9.76 dBi and the measured impedance bandwidth as much 2.5 GHz which is 4.7% more compared to the fundamental mode, TEy 1δ3. The result should be considered suitable for 5G applications
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