Showing papers presented at "International Workshop on Antenna Technology in 2020"

28/39-GHz Dual-Band Dual-Polarized Millimeter Wave Stacked Patch Antenna Array for 5G Applications

Abstract: In this paper, a novel high gain dual-band dual-polarized patch antenna array is proposed. This novel stacked capacitive coupled patch antenna array achieves high gain and wide bandwidth with a small size. The design of the antenna takes the problem of cost and processing accuracy into account to a great extent. The results show that the antenna array covers the frequency range of 24-28 GHz and 37-43 GHz, which are promising bands for future 5G based mobile services and it could be with a lot of potential for 5G applications.

Indoor Positioning using Decawave MDEK1001

Abstract: The problem of determining the object’s position has recently become an active research area, due to the increased demand for accurate outdoor and indoor positioning. This paper presents a preliminary testing campaign of the Decawave MDEK1001 development kit which uses UWB transmissions to determine the position of a tag in a real-time location system. The performance is evaluated in terms of positioning accuracy, and measurement error variation of the tag coordinates. The results analysis highlights the potential of the system and provides guidelines on how to increase the positioning accuracy.

Circularly Polarized Square Patch Array Antenna with Multiple Rectangular-Slots Fed by Proximity Coupling Technique

Abstract: This paper deals with the development of circularly polarized square patch array antenna for 5GHz wireless local area network (WLAN) application. One of essential benefits applying circularly polarized array antenna is the capability in minimizing the Faraday effect. The proposed array antenna consists of 5 microstrip square patch elements designed on 2 layers of FR4 dielectric substrate with 0.8mm thick of each layer. Each square patch element with multiple rectangular-slots to achieve circular polarization is fed by using proximity coupling technique to improve the radiation characteristics. Some investigations upon the geometry of array antenna as well as its feeding lines are carried out through simulation to gain an optimum architecture design implemented for hardware realization. The characterization results show the realized array antenna with the dimension of 119mm $\times$ 44.1mm could achieve the gain more than 6dBi around the frequency of 5GHz with the 3dB axial ratio bandwidth of 262MHz.

Impact of Electromagnetic Properties of Textile Materials on Performance of a Low-Profile Wearable Antenna Backed by a Reflector

Abstract: This paper focuses on the characterization of the electromagnetic (EM) properties of textiles (polar fleece, cotton, denim, polyester, and polyamide-elastane) and study of their impact on the performance of a wearable antenna. EM properties are measured by the cavity perturbation method, and it is found that the textile materials exhibit low values of complex relative permittivity between 1. $2+i0.002$ and 1. $9+i0.1$. A hexagonal-shaped monopole antenna with a substrate from polar fleece and high body-antenna isolation (front-to-back ratio 31 dB) is designed to serve the performance baseline. Additionally, prototypes on cotton, denim, polyester, and polyamide-elastane substrates are simulated, fabricated, and measured. Results show that radiation efficiency, gain and directivity decrease with increasing dielectric losses in the textile substrate. Further numerical investigations reveal that each of these five textile antennas achieves stable on-body performance in the frequency range of 2.4 to 2.5 GHz when it is placed on a flat phantom.

Performance Evaluation of the UWB-based CDS Indoor Positioning Solution

Abstract: Ultra-wideband technology has become very popular for accurate indoor positioning due to its resilience to interference with other technologies or resulting from multipath propagation. In this context, the scope of this paper is to evaluate the UWB-based indoor localization kit developed by Control Data Systems for accurate positioning of an operator relative to an industrial equipment. The kit is based on the VN360 UWB Module integrating the Decawave DW1000 IC and consists of 4 UWB anchors with a predetermined relative position and one UWB tag (for the operator). The accuracy of the evaluated solution is performed in terms of positioning error variation relative to the distance between the tag and the system origin.

MIMO Antenna Design for 5G Communication Systems Using Salp Swarm Algorithm

Abstract: Multiple Input Multiple Output (MIMO) antennas will be a part of every new user device in 5G networks. In this paper, we design a MIMO antenna for 5G networks using a nature-inspired algorithm, namely the Salp Swarm Algorithm (SSA). We select a bow tie antenna as the element of the MIMO operating in n257 frequency band (center frequency at 28GHz). Firstly, we design and optimize the antenna element using the SSA algorithm. Secondly, a MIMO antenna is designed using the optimal dimensions of the antenna element. Numerical results demonstrate that the proposed MIMO antenna has a small size and exhibits wideband operation in the desired frequency band.

Polymer-based 2.4 GHz Patch Antenna

Abstract: A highly flexible and conformable polymer-based patch antenna, based on commercial off-the-shelf (COTS) room temperature vulcanized silicone (RTV) silicone rubber substrate combined with a stretchable silver conductor, is presented. The measured performance of the antenna is compared with a reference antenna, which uses the same RTV silicone rubber as substrate and polyimide with copper cladding for the top layer and the ground plane. The measured gain of the polymer-based antenna is $\sim$ 4 dB lower compared to the reference antenna. This is also predicted by simulations and is due to the lower conductivity of the conductive polymer compared to copper in the reference antenna. The radiation pattern and gain of the polymer-based antenna remain mostly unaffected when the antenna is conformed to cylindrical surfaces of various radiuses.

5G Millimeter Wave Broadside-Endfire Antenna Array

Abstract: Metal frame presence in the modern mobile devices is been taken into consideration. Average uplink equivalent isotropic radiated power (EIRP) is defined for the full sphere beam scanning at cumulative distribution function (CDF)= 0.5 level, which dictates EIRP maximization for mmWave antenna solutions. These challenges have been addressed with a V-pol hybrid broadside-endfire antenna array. Presented solution shows good potential for possible implementation.

140 GHz Additive Manufacturing Low-Cost and High-Gain Fabry-Perot Resonator Antenna

Abstract: This paper presents a novel low-cost and high-gain fabry-perot resonator antenna (FPRA) at 140.0 GHz with additive manufacturing (AM) technology. A simple $2\times 2$ waveguide slot array is adopted as the feed antenna in this design. A layer of partially reflective surface (PRS), which is composed by two layers of metal grids and exhibits a positive reflection phase gradient over frequency, is placed above the feed antenna to improve the directivity radiation. To validate this design and meet the low-cost requirements, this antenna is printed by AM technique. Compared to previous high gain antennas, our design has the advantage of simple structure and low-cost because of applying fewer feeding networks and adopting 3-D printing technology.

Comparison Between Fully and Partially Filled Dielectric Materials on the Waveguide of Circularly Polarised Radial Line Slot Array Antennas

Abstract: This paper presents an investigation on the waveguide of circularly polarised radial line slot array (RLSA) antennas to improve gain and radiation bandwidth. Two circularly polarised (CP) RLSA antennas were designed with two different waveguide configurations. In the first configuration the waveguide is fully filled with dielectric materials and in the second configuration the waveguide is partially filled with dielectric materials and rest of the waveguide is filled with air. Numerical results of these two CP-RLSA antennas with two different waveguide configurations are presented and compared. Significant improvements have been made in the 3-dB directivity bandwidth and aperture efficiency of the antenna having waveguide partially filled with dielectric material. The 3-dB directivity bandwidth was measured 6.2% and aperture efficiency increased to 55.5%. The CP-RLSA antenna has also achieved a peak directivity of 31.7 dBic and a gain of 31.2 dBic as compared to the directivity 30.1 dBic and gain 29.5 dBic, respectively achieved with the CP-RLSA antenna having waveguide fully filled with dielectric material.

The Effects of Ground-Plane of a Textile Higher Mode Microstrip Patch Antenna on SAR

Abstract: This work studies the human exposure to EMFs that are generated by textile microstrip patch antenna and proposes a generalized methodology to reduce it. First, an antenna -commonly used for wearable applications- that highly interacts with the human body is investigated. To reduce exposure, the radiation directed onto the body is controlled by resizing the ground-plane. Despite this modification, the antenna maintains acceptable performance, its low profile, and low material and fabrication costs. Simulations show that as the ground-plane increases: (i) back radiation is mitigated leading to significant SAR reduction; (ii) the antenna interacts less with the human phantom and demonstrates acceptable performance. As the antenna under investigation is a typical one for body-centric communications and the ground-plane resize is a simple procedure, the proposed methodology may be applied to a vast variety of wearable applications.

Metantennas: Flat Luneburg Lens Antennas Using Transformation Optics Method (TOM)

Abstract: Luneburg lens has long been developed since first being proposed in 1944. The Luneburg lens is a spherical lens generally having a gradient of decreasing refractive index radially out from its center. The focusing properties of the Luneburg lens can be achieved through an infinite number of refractive-index solutions. With the spherically symmetrical structure and gradient radial refractive index change, the Luneburg lens is an excellent candidate for all-directional beamscanning antennas. This paper presents two types of flat Luneburg lens antenna based on printed circuit board technique for beamscanning applications. The transformation optics is used to flatten the design of conventional spherical Luneburg lenses and the technology based on metamaterials is proposed to implement the gradient index lens structure.

Reader Antennas Requirements in Chipless RFID Systems with Linear and Circular Polarization

Abstract: Two efficient reading approaches for chipless RFID are compared. The first approach uses a linear polarization interrogation with depolarizing tags able to reflect an electromagnetic signal with orthogonal polarization state with respect to the impinging one. In the second approach a circular polarization interrogation is sent to the tag which scatters it back with opposite rotation sense. The two methods are described in terms of both conversion efficiency and performance at a system level. It is underlined that one of the main requirements for obtaining good performance of the chipless RFID system relies on the design of the reader transmitting and receiving antennas which should be wideband and guarantee a low level of radiated cross-polarization, together with a low-mutual coupling.

3D-Printed Barcodes as RFID Tags

Abstract: In this paper we demonstrate the transformation of optical barcode into UHF RFID tag, which makes the barcode readable by both an RFID reader and an optical reader. The designed structure is fully realized by 3D Printing Technology including both dielectric and conductive components. The tag is provided with a -15 dBm sensitivity RFID chip (Impinj Monza 3) and can be scanned through both a barcode reader and a canonical UHF RFID reader. An RFID read range of 2m is demonstrated which represents an appreciable distance considering the chip sensitivity and the prototyping technique.

Design of a conventional horn antenna for Ku band

Abstract: In this paper are presented the design and the simulation of a broadband pyramidal horn antenna for satellite applications. The design was performed using the method of approximation and the final simulations were performed with HFSS. The proposed antenna operates in the frequency range 12-18 GHz (Ku band). A linearly polarized rectangular guide is used for feeding. The results of the simulations exhibit low voltage standing wave ratio and good radiation properties for the Ku band.

An Efficient Photomixer Based Slot Fed Terahertz Dielectric Resonator Antenna

Abstract: A slot fed THz dielectric resonator antenna driven by an optimized photomixer is presented. The localized optical E-field at the centre of the photomixer electrodes has been improved to 9.9V/m by utilizing a frequency selective surface superstrate. This corresponding to an enhancement factor of 4.7 compared to a conventional photomixer, which results in a considerable improvement in the optical-to-THz conversion efficiency. Moreover, the utilization of THz DRA offers a broadside gain of 9dBi and an input resistance of $700\omega$.

Dual-Polarized Probe for Millimeter-Wave Multi-Probe Spherical Near Field Measurement System

Abstract: In this paper a broadband dual-polarization probe has been designed and simulated which can be used for 5G millimeter-wave frequency band (below 50GHz) measuring. The probe not only has a wide impedance matching bandwidth, but also has no deterioration of the pattern of the interested frequency band. At the same time, the structure is simple and occupy small volume. The simulation results show that the impedance bandwidth of the probe proposed to this paper is 6-50GHz, and the isolation between the ports is more than 30dB in the whole frequency band, and it has good radiation performance and cross-polarization level. Therefore, this probe can find a scene in 5G millimeter wave frequency band measurement application, especially in multi-probe spherical near-field measurement system.

Effect of the Size and Shape of the Ground Plane in Small Antennas Efficiency

Abstract: An analysis of the radiation efficiency depending on the position of a small antenna and the size and shape of the ground plane is presented. For the analysis a LTCC based chip antenna has been used placing it on FR4 square, circular and triangular PCBs. The study is an insight of the key points for obtaining proper radiation efficiency in designs for the new licensed 5G IoT bands (600 MHz-USA, 700 MHz-Europe) and the ISM bands (868 MHz-Europe, 915 MHz-USA).

Localization in 802. 15.4z Standard

Abstract: The 802.15.4z standard, still under development, advances the secure ranging protocol by encryption of PHY timestamp sequence using AES-128 encryption algorithm. The paper analyses the key parts of PHY which have a great contribution in range estimation precision, particularly: UWB pulse, channel sounding and timestamp estimation using ciphered sequence. The propagation analysis in UWB channel shows that the frequency selective fading gives worse effects than multipath propagation in the timestamp estimation.

High Gain On-Chip Hemispherical Dielectric Resonator Antenna for 60 GHz Applications

Abstract: This paper explores how varying the structure of an on-chip 60 GHz dielectric resonator antenna (DRA) affects radiation characteristics such as gain, bandwidth and efficiency. Three configurations have been considered a standalone antenna, antenna with a single dielectric superstrate, and antenna with a dielectric superstrate as well as a parasitic substrate. A considerably high broadside gain of 12.4 dBi been achieved when the superstrate and parasitic substrate (SPS) are utilized. This has been achieved in conjunction with a 7.2% impedance bandwidth and a radiation efficiency of 81.6 %. All optimizations have been done using CST and cross-validated using HFSS.

An ISA100.11a Model Implementation for Accurate Industrial WSN Simulation in ns-3

Abstract: This paper presents the implementation and experimental validation of an ISA100.11a simulation model for industrial wireless sensor networks (IWSN). High simulation accuracy is achieved by integrating in ns-3 simulator the software stack running on the field devices. The same IWSN is implemented on both an experimental setup employing commercial hardware and a simulation scenario. The evaluation is performed in terms of specific network formation and operation metrics, highlighting the potential of the proposed model to accurately predict IWSN behavior.

Antenna design for a cranial implant

Abstract: This contributions presents the design process for an antenna designated for the telemetry in a cranial implant. Issues like physical limitation, simulation problems and design strategies will be addressed and final design presented.

Modified Patch Antenna Design Using Moth Search Algorithm for RF Energy Harvesting Applications

Abstract: Radio frequency energy harvesting is a well-promising technique to power wireless sensor network devices that require small amounts of energy to operate. It can be utilized as an alternative technique for power-constrained systems, such as wireless sensor networks with limited battery lifetime, by extending their energy supply. In outdoor environments, the dominant ambient radio wave sources are the broadcasting and the mobile communication networks. In this paper, we apply an optimization technique by utilizing Moth Search algorithm to design a modified microstrip patch antenna of three varying slots. The proposed antenna exhibits tuning operation in the LoRa (Long Range) and the cellular communications frequency bands of GSM-1800 and UMTS. Numerical results exhibit an acceptable performance of the proposed antenna for RF energy harvesting applications.

A Low Profile, UWB Circular Patch Antenna with Monopole-Like Radiation Characteristics

Abstract: a simple ultra-wideband antenna with monopolelike radiation pattern is presented in this paper. The structure of this low profile antenna with height of the 7 mm (0.65 ; min ) is based on annular-ring circular patch. To improve the antenna’s bandwidth, the main annular-ring circular patch is loaded with two concentric rings and two rectangular slots. The result shows the antenna achieves a 10 dB return loss bandwidth from 2.85 GHz to 8.6 GHz. The monopole-like radiation pattern is maintained throughout the frequency bands by combining four propagation modes of TM 01 , TM 02 , and TM 03 .

Gain tunability of graphene patch antennas for the ISM band at 24 GHz

Abstract: In this paper, we present a coplanar patch antenna (CPA), based on a graphene monolayer deposited on a thin film of zirconium-doped hafnium oxide ferroelectric (HfZrO), working at 24 GHz. The proposed antenna has been designed, simulated, fabricated and measured according to the requirements of an indoor localisation system based on a Frequency-Modulated Continuous-Wave (FM-CW) radar in the 24 GHz (24-24.25 GHz) ISM band with small codified tags to add identification functionality. The graphene CPA (GCPA) shows a 3 dB-enhancement of the gain in the direction of maximum radiation when applying a DC bias of -25 V. Then, a realistic case of study with a $4\times 4$ array is presented, showing the feasibility of the G-CPA for a 24 GHz-radar suitable for next-generation 5G telecommunications systems.

A Simple Printed Dipole Antenna with Broadband Characteristics

Abstract: This paper presents a microstrip-fed printed dipole antenna (PDA) which can cover a wide frequency band (roughly 80% for $|\mathrm{S}_{11}| \gt$ -$6 \mathrm{d}\mathrm{B}$), and maintain the omnidirectional radiation patterns in the entire operation band. The antenna shape is very simple. Two identical arms of the antenna upon two sides of an FR-4 substrate are placed inversely to each other and their shapes are similar to that of an inset-fed rectangular patch antenna. Our results show that the proposed antenna is very capable for many applications of small antennas while it has the compact size of $ 0.3\lambda\times 0.008\lambda$ at the minimum operation frequency of $|\mathrm{S}_{11}|=-6\mathrm{d}\mathrm{B}$.

Numerical Analysis of Dielectric Post-Wall Waveguides

Abstract: Functional post-wall waveguides that are formed by periodically distributed dielectric posts are numerically analyzed. In this preliminary study, the propagation constant and attenuation constant of the dielectric post-wall waveguide is rigorously calculated using our originally developed numerical method. The developed formulation is accurate and numerically very fast. Structural parameters of the dielectric post-wall waveguide are properly chosen in order to achieve the confinement of the field in the guiding region as strong as possible even in case of one-layered dielectric structure. The final goal of our investigations is to realize the functional dielectric post-wall waveguide-based filters, which are expected to have a practical application in THz region, where the metallic (PEC) rods are losing their properties.

Analytical Comparison of Blackman and Kaiser Functions for Power Weighted Linear Array Antennas with Small Number of Elements

Abstract: One method to gain desired radiation characteristics from some linear array antennas is by implementing an appropriate power weighted function upon the elements of array antennas. In this paper, analytical comparison of two power weighted functions, i.e. Blackman and Kaiser, is investigated for linear array antennas with small number of elements. Some linear array antennas with small odd and even number of elements are used to implement the weighting coefficient based on Blackman and Kaiser functions at the X-band frequency of 9.5GHz. The use of both functions is intended to have some expected radiation characteristic in terms of width of mainlobe (WML) and sidelobe level (SLL). The analysis result shows that Blackman function with small number of elements could achieve the radiation characteristics with predefined SLL of 68.8dB and inter element spacing of $\lambda$/1.5, but with some WML enhancement. This performance is better in SLL suppression than Kaiser function with predefined SLL of 68.8dB and $\beta$ of 6.623.

Simulation and Optimization of the Design of Focusing Dielectric Lenses based on Cartesian Ovals with Physical Optics

Abstract: This paper presents the design of a focusing dielectric lens, which is described by a so-called Cartesian oval. The mathematical model of Cartesian ovals is introduced briefly. Next, a physical optics (PO) approach for the simulation of the electric field outside of the antenna is presented. Simulation results at 80 GHz are shown. The agreement between a full wave reference method and the proposed method is good, especially in the focal region. The simulation time is decreased significantly by the asymptotic PO approach compared to the finite integration technique. Eventually, a lens design is optimized with the PO to achieve the desired focal point.

Circularly Polarized Antenna in 3D Printing Technology to Feed a Wearable Fully-Integrated WiFi-RFID Reader for Biomedical Applications

Abstract: In this work, a compact, low-profile, portable RFID reader suitable for medical applications has been proposed and its antenna designed, realized and tested. Specifically, a circularly polarized UHF RFID reader antenna conformal to a dielectrically controlled plastic support is proposed. The radiating element has been realized through a circular array of four inverted-F monopoles, where the array elements are excited with a 90-degree phase offset (sequential rotation feeding technique) through a microstrip feeding network. To allow for a friendly prototype realization, the antenna structure is thought to be shaped on adhesive copper and the dielectric support to be 3D-printed in Poly-Lactic Acid (PLA), opportunely selected due to interesting low losses properties. The very compact antenna (60mm x 60mm x 6.5mm), suitable for the desired portable Reader, has been characterized in terms of reflection coefficient, port isolation and radiation patterns.