Mohamed Nasrun Osman

Compact Dual-Port Polarization-Reconfigurable Antenna With High Isolations for MIMO Application

This letter proposes the design of a dual-port microstrip patch antenna with polarization reconfigurability features. The reconfigurability is realized through the modification of the feed network. The antenna consists of a circular-shaped patch on the upper substrate as a radiating element, and a coplanar-waveguide (CPW) slotline transmission located in the ground plane. To obtain a good impedance matching, the CPW slotline is terminated with a tapered impedance transformer. Dual ports are constructed by utilizing the CPW feeding structure and the odd and even feedline modes of the CPW. Four p-i-n diodes are used as switches to alter the flow of the current. The p-i-n diodes are placed on the CPW transmission slotline interjunction. Consequently, the excited polarization can be altered and determined, depending on the switch configurations. This antenna demonstrates good port-to-port isolation and a compact structure and is suitable to be used in systems that operate in a wireless local area network (WLAN) frequency band.

Textile Antenna With Simultaneous Frequency and Polarization Reconfiguration for WBAN

This paper proposes the design of a reconfigurable circularly polarized textile antenna. The circular polarization feature in the proposed antenna is generated by the edge truncation of a rectangular patch and the incorporation of a slotted ground plane, whilst the frequency reconfigurability feature is realized by slot size modification via the use of three embedded RF p-i-n diode switches. Consequently, the antenna operation can be switched between six frequencies (1.57, 1.67, 1.68, 2.43, 2.50, and 2.55 GHz) depending on the seven switch configurations. The proposed antenna is validated experimentally to be operable within the WBAN, WLAN, and GPS range in a compact and wearable format, with gains of up to 4.8 dBi.

Analysis of circular polarization textile antenna in bending condition

A circular polarization (CP) textile antenna is designed for Global Positioning System (GPS) application. The truncated rectangular patch antenna is has a full ground plane from Shieldit Super and felt fabric as a substrate. The proposed antenna operates at 1.575 GHz with a good bandwidth from 1.540 to 1.625 GHz. The optimized chamfer has been made at two edges of a rectangular patch in order to produce a Left Hand Circular Polarization (LHCP) with a good axial ratio (AR) badwidth of 1.569 to 1.589 GHz. This manuscript also presents the analytical performances of CP textile antenna under bending condition that suitable for the on-body antenna applications.

Indoor Channel Capacity Measurement of 2 x 2 MIMO Polarization Diversity Antenna

With the rapid growth of communications via the Internet, the need for an effective firewall system which has not badly affect the overall network performances has been increased. In this paper, a Field Programmable Gate Array (FPGA) -based firewall system with high performance has been implemented using Network FPGA (NetFPGA) with Xilinx Kintex-7 XC7K325T FPGA. Based on NetFPGA reference router project, a NetFPGA-based firewall system was implemented. The hardware module performs rule matching operation using content addressable memory (CAM) for higher speed data processing. To evaluate system performance, throughput, latency, and memory utilization were measured for different cases using different tools, also the number of rules that an incoming packet is subjected to was varied to get more readings using both software and hardware features. The results showed that the designed firewall system provides better performance than traditional firewalls. System throughput was doubled times of the one with Linux-Iptables firewalls.

A dual band antenna design for future millimeter wave wireless communication at 24.25 GHz and 38 GHz

This paper proposes a dual band antenna for future millimeter wave wireless communication. The performance of this dual band antenna is analyzed in term of reflection coefficient when some of the length of the patch antenna was adjustable, overall gain and total efficiency for both frequencies respectively. The size of this presented patch antenna is 4.9 × 7.6 mm2. The dual band antenna was fabricated on a RTRogers5880 with a dielectric constant of £=2.2 and thickness of the substrate is 0.127 mm. The simulated result obtained the reflection coefficient as a requirement of the antenna which is not less than −10 dB for 24.25 GHz and 38 GHz that capable to cover 5G applications. The proposed antenna has achieved a maximum gain up to 5.5 dBi and 4.5 dBi at desired frequencies respectively. All design and simulation are carried out using CST Microwave Studio software. The proposed antenna design could be suitable to be applied as a device to the 5G wireless system.

Dual-port polarization reconfigurable antenna using compact CPW slotline feeding structure for space-limited MIMO application

In this paper, dual-port polarization reconfigurable circular patch antenna is proposed. The polarization reconfigurability is achieved by modifying the coplanar waveguide (CPW) slotline feeding network located on the ground plane. Two quarter wavelength phase delays are interconnected on each of the slot lines. Eight switches are placed on the CPW slotline transmission to activate and deactivate the phase delay slotlines, which controlled the flow of the current and consequently changed the polarization mode of the antenna. The dual port feature is realized by utilizing the odd and even mode of the CPW characteristic. Simulation results demonstrate the proposed antenna has the capability to switch the polarization excited, whilst maintaining good impedance matching and port-to-port isolation.

A Comparative Study on Polarization Reconfigurable Circular Patch Antenna

This paper presents a comparison between two approaches of designing polarization reconfigurable antennas. To achieve this special feature, it can be realized by introducing perturbation elements into the radiating components of the structure. Secondly, it also can be accomplished by altering the feeding networks, without any modification needed to the radiating elements. Both approaches are executed to the conventional circular patch microstrip antennas. For reconfigurability purposes, the switches are placed at the specific location. Consequently, by controlling the state of the switches (either ON or OFF), the polarization excites by the antenna can be reconfigured between three type of polarization modes, either left-hand circular polarization, right-hand circular polarization or linear polarization. For the proof of the concept, ideal case of switch (copper strips) is employed in the designs. Both of the structures are designed to operate in wireless local area network (WLAN) frequency band (2.4–2.48 GHz). The performances of both designs are presented and compared, and the advantages and disadvantages of the proposed design are discussed.

Polarization reconfigurable patch antenna through modification of feeding network

This paper proposes an antenna with ability to reconfigure the polarization between linear polarization, right-hand circular polarization and left-hand circular polarization through the modification of the feeding network. The antenna consists of circular patch on the upper side of the substrate, and the coplanar waveguide transmission line is placed on the ground plane at the underside of the substrate. For reconfigurability purpose, eight switches are applied and positioned at the feeding network. The performance of the proposed antenna is presented and discussed. The proposed antenna is operated within WLAN frequency band (2.4-2.48 GHz).

Polarization reconfigurability patch antenna with improved axial ratio bandwidth

In this paper, the patch antenna with polarization reconfigurability feature is proposed. The antenna composed of circular patch on the top substrate embedded with four equal-length slits, and is fed at the diagonal of the structure using the coaxial fed technique. To obtain the reconfigurability feature, four switches (copper strips) are appropriately located at the specific position across the slit. This will change the slot length, and then consequently altered the polarization excited by the antenna. By controlling the state of the switch, the polarization of the proposed antenna is able to be reconfigured between linear polarization, left-hand circular polarization and right-hand polarization. Triple layers of substrate are utilized in the design in order to have the broader axial ratio bandwidth. The simulated results of the proposed antenna are presented and discussed. This antenna is operated and covered the whole wireless local area network (WLAN) frequency band.

Circular patch antenna design with switchable polarization

In this paper, a circular patch antenna with polarization reconfigurability is proposed. The proposed antenna has a simple structure, consists of a radiating circular patch and two equal length perturbation slits located on the top layer of the substrate with finite ground plane on the bottom layer. In the design, two switches are used and located at the specific distance in the slits. By controlling the state of the switches, the proposed antenna is capable to produce three type of polarizations, which is linear polarization (LP), right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The key parameters of the proposed antenna are investigated and the details of the design and simulation results are discussed. The reconfigurable antenna with polarization diversity is operated at wireless local area network (WLAN) frequency band.