Optimization of Multi-Band Characteristics in Fan-Stub Shaped Patch Antenna for LTE (CBRS) and WLAN Bands

This study aims to optimize a fan-stub slot patch to get better suitability and performance for Citizens Broadband Radio Service (CBRS). The transition from the tedious configuration of slotted patch antenna in fan-stub shape is evaluated. Also, the impact of stub width W, stub length L, and its orientation are tested. Multiple simulation tests ensure the uniqueness in the type of slots or stubs that affect the multiband nature of patch. The optimization of basic fan-stub structure on return loss S11, Voltage Standing Wave Ratio (VSWR), and the operating band at the desired frequency is performed to accommodate the federal and non-federal use of the band. The simulation results show that the designed antenna is technically suitable to cover 4G LTE in CBRS (LTE-43 and LTE-48 band) as well as 5.5 GHz Wireless Local Area Network (WLAN) band of operation

Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications

For many designers, embedded antenna design is a very challenging task when designing embedded systems. Designing Antennas to given set of specifications is typically tailored to efficiently radiate the energy to free space with a certain radiation pattern and operating frequency range, but its design becomes even harder when embedded in multi-layer environment, being conformal to a surface, or matched to a wide range of loads (environments). In an effort to clarify the design process, we took a closer look at the key considerations for designing an embedded antenna. The design could be geared towards wireless/mobile platforms, wearable antennas, or body area network. Our group at UT has been involved in developing portable and embedded systems for multi-band operation for cell phones or laptops. The design of these antennas addressed single band/narrowband to multiband/wideband operation and provided over 7 bands within the cellular bands (850 MHz to 2 GHz). Typically the challenge is: many applications require ultra wide band operation, or operate at low frequency. Low frequency operation is very challenging if size is a constraint, and there is a need for demonstrating positive antenna gain

The Study of Reconfigurable Antennas and Associated Circuitry

This research focuses on the design of pattern reconfigurable antennas and the associated circuitry. The proposed pattern reconfigurable antenna designs benefit from advantages such as maximum pattern diversity and optimum switching circuits to realise 5G reconfigurable antennas. Whereas MIMO based solutions can provide increased channel capacity, they demand high computational capability and power consumption due to multiple channel processing. This prevents their use in many applications most notably in the Internet of Things where power consumption is of key importance. A switched-beam diversity allows an energy-efficient solution improving the link budget even for small low-cost battery operated IoT/sensor network applications. The main focus of the antenna reconfiguration in this work is for switched-beam diversity. The fundamental switching elements are discussed including basic PIN diode circuits. Techniques to switch the antenna element in the feed or shorting the antenna element to the ground plane are presented. A back-to-back microstrip patch antenna with two hemispherical switchable patterns is proposed. The patch elements on a common ground plane, are switched with a single-pole double-throw PIN diode circuit. Switching the feed selects either of two identical oppositely oriented radiation patterns for maximum diversity in one plane. The identical design of the antenna elements provides similar performance control of frequency and radiation pattern in different states. This antenna provides a simple solution to cross-layer PIN diode circuit designs. A mirrored structure study provides an understanding of performance control for different switching states. A printed inverted-F antenna is presented for monopole reconfigurable antenna design. The proposed low-profile antenna consists of one main radiator and one parasitic element. By shorting the parasitic element to the ground plane using only one PIN diode, the antenna is capable of switching both the pattern and polarisation across the full bandwidth. The switched orthogonal pattern provides the maximum spatial pattern diversity and is realised using a simple structure. Then, a dual-stub coplanar Vivaldi antenna with a parasitic element is presented for the 5G mm-Wave band. The use of a dual-stub coupled between the parasitic element and two tapered slots is researched. The parasitic element shape and size is optimised to increase the realised gain. A bandpass coupled line filter is used for frequency selective features. The use of slits on the outer edge of the ground plane provides a greater maximum gain. This integrated filtenna offers lower insertion loss than the commercial DC blocks. The UWB antenna with an integrated filter can be used for harmonic suppression. The influence of the integrated filter circuit close to the antenna geometry informs the design of PIN diode circuit switching and power supply in the 5G band. Based on the filter design in the mm-Wave band, a method of designing a feasible DC power supply for the PIN diode in the mm-Wave band is studied. A printed Yagi-Uda antenna array is integrated with switching circuitry to realise a switched 180° hemispheres radiation pattern. The antenna realises a maximum diversity in one plane. The study offers the possibility to use PIN diodes in the mm-Wave band for reconfigurable antenna designs. For the presented antennas, key geometric parameters are discussed for improved understanding of the trade-offs in radiation pattern/beamwidth and gain control for reconfigurable antenna applications

Design of chipless UWB RFID system using A CPW multi-resonator

In this paper, the design of a novel chipless ultra-wideband radio-frequency identification (UWB RFID) system is proposed. The system employs printable uniplanar chipless tags and a pair of high-gain reader antennas. The chipless tag is composed of two UWB monopole antennas, connected by a coplanar waveguide (CPW). The tag's ID is represented by a spectral signature in the UWB frequency range, and is created by a multi-resonator embedded on the coplanar waveguide. The detection of the tag's ID is based on using only the amplitude of the spectral signature, which significantly simplifies the complexity of detection. The reader employs two separate Vivaldi antennas-one for transmitting a vertically polarized signal, and the other for receiving a horizontally polarized signal-to reduce the mutual coupling between the uplink and downlink signals. Further reduction of mutual coupling is achieved by using a copper plate at the reader to separate the uplink and downlink signals. These two proposed methods together reduced the mutual coupling by 20 dB. The chipless RFID tag with eight coplanar waveguide resonators in a group and the reader antennas were designed using computer simulation, and fabricated on Rogers substrates for measurement. The results of studies in an anechoic chamber showed that the proposed UWB RFID system could achieve a reading range of larger than 30 cm, at least three times longer than the maximum distance of a similar system reported by others. This indicated that the proposed system has great potential for short-range item tracking at low cost. © 1990-2011 IEEE.published_or_final_versio

A Planar Dual Notched Band Vivaldi Antenna for Wireless Communication Applications

With the aim of realizing a Vivaldi Antenna (VA) with stop bands for wireless communication applications, this paper introduces a novel, uncomplicated, easily fabricated, and compact planar VA featuring two distinctive rejected frequency bands. The designed VA is engraved onto an FR4-epoxy substrate, measuring 0.4243λ0×0.4296λ0 ×0.01315λ0 at 2.63 GHz. The integration of dual notched band functionality is ingeniously achieved through the implementation of a simple additional strip and a U-formed slit. A physical prototype of the VA was successfully constructed and meticulously measured with the R&S®ZNB Vector Network Analyser. The measured impedance bandwidth demonstrates that the realised VA operates from 2.63 GHz to beyond 12 GHz while effectively excluding two bands: 3.46-4.16 GHz (18.37 %) and 5.32-6.5 GHz (19.97 %). Simulated results indicate that the designed VA can provide stable unidirectional radiation patterns, reasonable realized gain, and acceptable radiation efficiency across its operating ranges, with notable drops observed at the two notched bands. As a result, these findings highlight the practical value of the designed VA for wireless communication applications, particularly in scenarios where the integration of filtering structures in antennas becomes essential to prevent interference with co-existing systems. The presented VA opens new avenues for enhancing wireless communication performance, catering to the increasing demand for reliable and interference-resistant solutions

Antenna Design for 5G and Beyond

With the rapid evolution of the wireless communications, fifth-generation (5G) communication has received much attention from both academia and industry, with many reported efforts and research outputs and significant improvements in different aspects, such as data rate speed and resolution, mobility, latency, etc. In some countries, the commercialization of 5G communication has already started as well as initial research of beyond technologies such as 6G.MIMO technology with multiple antennas is a promising technology to obtain the requirements of 5G/6G communications. It can significantly enhance the system capacity and resist multipath fading, and has become a hot spot in the field of wireless communications. This technology is a key component and probably the most established to truly reach the promised transfer data rates of future communication systems. In MIMO systems, multiple antennas are deployed at both the transmitter and receiver sides. The greater number of antennas can make the system more resistant to intentional jamming and interference. Massive MIMO with an especially high number of antennas can reduce energy consumption by targeting signals to individual users utilizing beamforming.Apart from sub-6 GHz frequency bands, 5G/6G devices are also expected to cover millimeter-wave (mmWave) and terahertz (THz) spectra. However, moving to higher bands will bring new challenges and will certainly require careful consideration of the antenna design for smart devices. Compact antennas arranged as conformal, planar, and linear arrays can be employed at different portions of base stations and user equipment to form phased arrays with high gain and directional radiation beams. The objective of this Special Issue is to cover all aspects of antenna designs used in existing or future wireless communication systems. The aim is to highlight recent advances, current trends, and possible future developments of 5G/6G antennas

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