Design of broadband circularly polarised printed monopole antennas for indoor wireless communication systems

With the rapid changes in wireless communication systems, indoor wireless communication (IWC) technology has undergone tremendous development. Antennas are crucial components of IWC systems that transmit and receive signals within indoor environments. Thus, the development of indoor technology is highly dependent on the development of indoor antennas. However, indoor environments with a limited space require the fewest number of indoor antenna units and the smallest indoor antenna size. Hence, indoor antennas with a compact size and broad applications have become widely preferred. In an IWC tem, the use of circularly polarised (CP) antennas is generally important, especially in dense indoor environments, because relative to linearly polarised (LP) antennas, CP antennas reduce polarisation mismatch and multipath losses. Conventional broadband CP antennas have been used for IWC systems. However, these antennas are bulky in size and feature a heavy profile. They are also expensive and difficult o design and fabricate. Thus, broadband CP printed monopole antennas (BCPPMAS) have received considerable attention in the field of wircless communication because of their compact size, low profile, low cost, simple structure and capability of providing broad impedance bandwidth (IBW) and axial ratio bandwidth (ARBW). However, these antennas have a difficulties in the trade-off between the antenna's bands (TBW and ARBW) with high overlapping percentage and their structure size which restricts their use in IWC sy Therefore, this thesis aimed to design a new structure for BCPPMAs which ew functionality for indoor antennas. Two design topology approaches for BCPPMAs were introduced: the biplanar topology approach based on the microstrip feeding technique and the uniplanar topology approach based on coplanar waveguide feeding (CPW-fed) using low-cost FR4 materials. All presented antennas provided bidirectional radiation patterns with different CP senses and good gain with small variations over the majority of the achieved CP band. The main proposed CP antenna_designs, namely, the P-shaped, L-shaped and modified rectangular-shaped BCPPMAS were simulated, fabricated and measured. The antennas provided broad IBW and ARBW greater than 100%, Moreover, the bandwidths showed a wide overlapping ratio between them of more than 89%. while the measured IBW and ARBW of the proposed modified rectangular CPW-fed BCPPMA are 108.5% (1.825-6.15 GHz) and 107.7% (1.8~ 6 Giz), respectively. This design retains a compact size of 35 mm x 35 mm and a wide overlapping percentage of 97%. The measurement results showed a good agreement with the simulation results. The benefits of the proposed antennas include broad IBW and ARBW, compact size and simple design. Hence, they are suitable candidates for IWC systems. The results of this work can facilitate improvements in broadband wireless communication systems and afford them with good tuning capabilite

Design And Investigation On Wideband Antenna Based On Polydimethylsiloxane (PDMS) For Medical Imaging Application

This paper presents an antenna for the medical imaging application which can detect unusual tissues on any part of the body. A compact design of wideband antenna with wearable properties is proposed for the medical imaging application. The wideband antenna is designed with introducing notches to the patch and a t-shaped slot at the partial ground. Polydimethylsiloxane (PDMS) is introduced to the antenna for the implementation of the wearable antenna. The proposed antenna operated in a frequency range of 3GHz to 6GHz. The antenna that embedded with PDMS shows a good agreement to the antenna without PDMS. An experimental proposed structure shows a good agreement with the simulated results. The overall dimension of the antenna is 24mm(W) x 38mm( L) which consider is a miniature antenna. This proposed design give an alternative solution for the antenna which cannot be wear on the body and protect the antenna. The introduction of PDMS will reduce the signal reflection cause by the high coupling of the human body

Electrical Equivalent Model Of Symmetrical Split Ring Resonator Sensor-Based Microwave Technology

In this paper, a microwave planar sensor based on symmetrical split ring resonator (SSRR) is investigated. This sensor uses ring resonator with slits at 0o and 180o angles as method to realize the harmonic resonant frequency response and then, it integrated with symmetrical split ring for suppressing the undesired harmonic spurious. Compact size, simplicity, cost effective, and ease of fabrication are the main advantage of SSRR sensor. The model of analytical equivalent circuit is proposed and the characteristic of band-pass and band-stop are derived and investigated for the analysed SSRR with/without spurliners filters. The performance and sensitivity of the SSRR sensor is high with an average accuracy between 96% to 98 % at narrow band frequencies. This type of resonators sensors can detect the material properties under their chemical or physical changes which is essential for numerous applications such as quality control, agriculture, bio-sensing, medicine and pharmacy, food industry, and material science

Accurate Characterizations Of Material Using Microwave T-Resonator For Solid Sensing Applications

The topic of microwave sensors in enclosures is one of the most active areas in material characterization research today due to its wide applications in various industries. Surprisingly, a microwave sensor technology has been comprehensively investigated and there is an industry demand for an accurate instrument of material characterization such as food industry, quality control, chemical composition analysis and bio-sensing. These accurate instruments have the ability to understand the properties of materials composition based on chemical, physical, magnetic, and electric characteristics. Therefore, a design of the T-resonator has been introduced and investigated for an accurate measurement of material properties characterizations. This sensor is designed and fabricated on a 0.787 mm-thickness Roger 5880 substrate for the first resonant frequency to resonate at 2.4 GHz under unloaded conditions. Various standard dielectric of the sample under test (SUT) are tested to validate the sensitivity which making it a promising low-cost, compact in size, ease of fabrication and small SUT preparation for applications requiring novel sensing techniques in quality and control industries

New CPW-Fed Broadband Circularly Polarized Planar Monopole Antenna Based On A Couple Of Linked Symmetric Square Patches

A new broadband circularly polarized planar monopole antenna with coplanar waveguide feeding (CPW-fed) is proposed. This antenna consists of a couple of linked symmetric square patches (CLSSP), an asymmetric ground plane and two strips connected to the left ground plane by the CLSSP radiator and a straight strip. A broad impedance bandwidth (IBW) is achieved. Moreover, a broad axial ratio bandwidth (ARBW) is obtained by using an asymmetric ground plane and an inverted L-shaped strip. Simulation results demonstrate that IBW reaches 119% (1.56-6.18 GHz) and ARBW is 88.9% (2-5.2 GHz). The latter is completely overlapped by the simulated IBW. In addition, antenna performance is investigated by studying different parameters

Design Of Helical Antenna For Next Generation Wireless Communication

This study proposes a novel helical antenna design for next generation applications. The strip helical antenna is prescribed for next generation wireless communication and wideband applications that offer circular polarization and a wide bandwidth. In fact, the proposed helical antenna suits 5.8 GHz frequency by using Teflon material. The newly-designed strip was printed on a substrate and rolled into a helix shape to achieve circular polarization without impedance matching. This antenna is meant for wideband wireless communication applications. A wide bandwidth of 2.7 GHz with 5.8 GHz resonant frequency was attained through the use of helical antenna on Teflon substrate. The proposed antenna on Teflon substrate recorded a gain of 8.97 dB and 92% efficiency. The antenna design parameters and the simulated results were retrieved using Computer Simulation Technology software (CST). The measurement result of return loss displayed mismatch at 5.22 GHz due to manual fabrication. This developed antenna may be applied for a number of wireless applications, including Wideband, Ultra-wideband, and 5G

Compact CPW-Fed Broadband Circularly Polarized Monopole Antenna With Inverted L-Shaped Strip And Asymmetric Ground Plane

The design of a coplanar waveguide-fed (CPW-fed) broadband circularly polarized printed monopole antenna is proposed. The antenna consists of a simple rectangular radiator monopole, an inverted L-shaped strip, a horizontal stub, and a modified asymmetric ground plane. Simulation results indicate that the impedance bandwidth (IBW) is 121% (1.575-6.4 GHz), and the axial ratio bandwidth (ARBW) is 64.3% (2.85-5.55 GHz). A parametric study is performed for verification. Results: indicate that the proposed antenna is suitable for different wireless communications systems

A Broadband P-Shaped Circularly Polarized Monopole Antenna With A Single Parasitic Strip

A new broadband circular polarization (CP) monopole antenna with simple structure is proposed. The antenna consists of a P-shaped monopole and modified ground plane with rectangular stub, and results demonstrated that the 10 dB impedance bandwidth (ZBW) is 118.5% (1.6–6.25 GHz) and the 3 dB axial-ratio bandwidth (ARBW) is 104.4% (1.9–6.05 GHz). Procedures to improve the proposed antenna design and the CP mechanism analysis were performed. The performance of different parameters is presented. The advantages of the proposed antenna are broader ZBW and ARBW, simpler structure, and compact size

Review Of Recent Trends On Power Amplifier Design For Modern Communication Systems

Next-generation wireless communication standard 5G requires power amplifiers capable of maintaining high efficiency in the presence of modulated signals with high Peak-toAverage Power Ratio (PAPR) in order to avoid signal clipping and distortion. Meanwhile, a wideband or multi-band capability is necessary for multi-standard applications. In this paper, a brief review of the most recent wideband and high-efficiency power amplifier designs was presented, with a particular focus on Doherty Power Amplifier (DPA) as the most suitable technique. A comparison between different efficiency enhancement techniques was discussed in detail, while the basic concept and principle of operation for the DPA were presented accordingly. Moreover, many innovative designs to enhance the power amplifier's performance in terms of the back-off efficiency and bandwidth extension were discussed. The first topic considered was efficiency enhancement, whereby different solutions such as multi-stage DPA, asymmetrical devices, and output combiner optimization were presented. Meanwhile, another significant topic discussed was bandwidth extension in which a large number of papers was discussed accordingly. Besides, the most important factors of DPA designs limiting the efficiency enhancement and bandwidth extension were highlighted. Most of the presented designs focused on a single approach, either efficiency enhancement or bandwidth extension. Therefore, symmetrical DPA based on the asymmetrical matching network in combination with multi-section impedance matching can be suggested to solve the problem of efficiency degradation at a Back-Off (BO) region. This will extend the bandwidth simultaneously in order to meet the requirements of modern wireless communication systems