Single-, Dual- and Triple-band Frequency Reconfigurable Antenna

The paper presents a frequency reconfigurable slot dipole antenna. The antenna is capable of being switched between single-band, dual-band or triple-band operation. The antenna incorporates three pairs of pin-diodes which are located within the dipole arms. The antenna was designed to operate at 2.4 GHz, 3.5 GHz and 5.2 GHz using the aid of CST Microwave Studio. The average measured gains are 1.54, 2.92 and 1.89 dBi for low, mid and high band respectively. A prototype was then constructed in order to verify the performance of the device. A good level of agreement was observed between simulation and measurement

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

A rapid and gentle method for the salt extraction of chromatin core histones H2A, H2B, H3 and H4 from rat liver nuclei

A complex of histones H2A, H2B, H3 and H4 has been isolated from purified rat liver nuclei by a method which is both gentle and rapid. Nuclei were homogenised in 0.25 I sucrose and the residual nuclear material obtained after centrifligation was adsorbed on calcium phosphate gel. After removing histone H1 from the adsorbed material by washing with 1M NaCl in 25 mM sodium phosphate buffer, pH 6.0, histones H2A, H2B, H3 and H4 were eluted together, with 2 I NaCl in 25 mM sodium phosphate buffer, pH 7.0. The core histones so obtained migrated as a single sharp band on polyacrylamide gel electrophoresis under non-denaturing conditions. Fractionation of the freshly prepared core histones on a Sephadex G-100 column yielded two major protein peaks. The peak having the larger elution volume contained histones H2A and H2B in equal amounts while the peak with the smaller elution volume contained all the four histones. Histones H3 and H4 were present in larger proportions in the second peak

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

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

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

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

Complementary split ring resonator for isolation enhancement in 5G communication antenna array

A square-shaped complementary split ring resonator (CSRR) filtering structure for isolation improvement is presented in this paper. The proposed research work investigates the design and development of a simple and compact CSRR structure. In order to verify the performance of the proposed filtering element and improve the isolation among the closely placed antenna elements, arrays of configured CSRR structures are implemented between two antenna elements. An array of configured CSRR elements has been integrated with the printed antenna on the top and bottom layers. The proposed filtering elements offer an enhancement in isolation by 25 dB as compared to the simple array. The entire configuration has been simulated using the Ansoft HFSS simulator. Finally, the proposed design is fabricated and experimentally validated. In the experiment, coupling suppression of -51 dB at the operating frequency is successfully achieved, resulting in a recovery of the array pattern. The proposed antenna is highly efficient, which is suitable to be utilized for 5G communication

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