Showing papers presented at "International Workshop on Antenna Technology in 2019"

Novel Integrated Design of Dual-Band Dual-Polarization mm-Wave Antennas in Non-mm-Wave Antennas (AiA) for a 5G Phone with a Metal Frame

Abstract: A novel integrated design of dual-band dual-polarization millimeter-wave (mm-Wave) antennas in a non-mm-Wave antenna (AiA) for a cellular phone with a metal frame and a high screen-to-body ratio over 91.5% for the fifth generation mobile communications (5G) is presented to achieve high compatibility with metal-exterior designs, good conformal ability to challenging product shapes, and compact space for the mmWave and non-mm-Wave antennas. The mm-Wave antennas based on 5 dual-band dual-polarization stacked patch antennas form a linear antenna array embedded in the metal frame which serves as a long-term evolution (LTE) antenna. From simulations, in terms of input reflection coefficients |Snn| ≥ -10 dB, the bandwidths of the vertical ports (V-ports) in the 5G mmWave antenna array for the vertical polarization (V-pol.) range from 27.44 GHz to 28.56 GHz and from 36.92 GHz to 40.22 GHz; similarly, the bandwidths of the horizontal ports (H-ports) in the 5G mm-Wave antenna array for the horizontal polarization (H-pol.) range from 27.32 GHz to 28.56 GHz and from 36.96 GHz to 40.34 GHz, respectively. Thus, the two popular 5G mm-Wave bands of n261 and n260 in the third generation partnership project (3GPP) can be covered. Besides, for the low band (band n261) and high band (band n260), the maximum (max.) peak realized gains of the V-pol. in the plane of theta = 90° are 11.49 dBi and 13.27 dBi, and the max. scanning angles are both 45°, respectively. Similarly, the max. peak realized gains of the H-pol. in the plane of theta = 90° in the low band and high band are 11.35 dBi and 12.18 dBi, and the max. scanning angles are 60° and 30°, respectively. The bandwidths of| Snn| ≤ -6 dB for the LTE antenna can cover from 872 MHz to 962 MHz and from 2265 to 2740 MHz so that LTE Band 8, Band 40, and Band 41 can be accommodated with antenna efficiencies higher than -3.43 dB in the low band (Band 8) and higher than -1.72 dB in the high band (Band 40 and Band 41). Also, the mm-Wave antenna array can attain right-hand and left-hand circular polarizations.

Improving LoRa Signal Coverage in Urban and Sub-Urban Environments with UAVs

Abstract: LoRa technology enables long-range communication with low-power consumption for the Internet-of-Things (IoT) devices in the urban and suburban environment. However, due to terrestrial structures in urban and suburban environments, the link distance of LoRa transmissions can be reduced. In this paper, we report signal strength measurements for the in-building and inter-building LoRa links and provide insights on factors that affect signal quality such as the spreading factor and antenna orientation. Subsequently, we also provide measurement results in urban and suburban environments when the LoRa transmitter is deployed at different heights using an unmanned aerial vehicle (UAV). Our findings show that the UAV deployment height is critical for improving coverage in the suburban environment and antenna orientation affects the communication range.

Triple Band MIMO Antenna System for 5G Mobile Terminals

Abstract: A 4-antenna array for multiple-input multiple-output (MIMO) applications in future fifth generation (5G) mobile terminals is presented in this paper. The antenna array consists of four triple band antennas which can cover 5G new radio (NR) including n77 (3.3-4.2GHz) and n79 (4.4-5GHz), and 5GHz-wireless wide area network (WLAN) operation in 5.15-5.85GHz. The proposed antenna array was fabricated and measured. The measured total efficiency over 60% and isolation better than 14dB between each port were obtained. Envelope correlation coefficient (ECC) and channel capacity (CC) were also analyzed to evaluate the antenna performance.

Circular Polarized RFID Tag Antenna Design using Characteristic Mode Analysis

Abstract: This paper presents a circularly polarised RFID tag antenna using characteristic mode analysis. The proposed design consists of a leaf-shaped radiator with two cross slots and shorting stubs etched on a grounded FR4 substrate. By analyzing the characteristic modes, the diagonal slots are created at suitable locations to enable modes to resonate in the required frequency band. In addition to this, edge rounding is performed to create modes with orthogonal current distribution for circular polarisation. Moreover, the RFID chip is placed as a capacitive coupling element at current minima to excite these orthogonal modes. Furthermore, the tag parameters are optimized to give a conjugate match with Alien H4 RFID chip in US UHF RFID band (902 – 928 MHz). The proposed tag provides a read range of 3.5 m and 5 m after mounting on low permittivity substrate and 100 × 100 mm2metallic plate, respectively.

Effect of the screen to metal-frame smartphone antennas

Abstract: In a recent couple of years, the smartphone's screen-to-body ratio is continuously increasing. Large-screen, or even full-screen (also called all-screen or bezel-less) smartphones are popular. However, the large-size and metal-contained screen may affect the performance of metal-frame smartphone antennas. But until now, there has not been systematic research published on the effect of the screen to smartphone antennas. In this paper, firstly the structure of the smartphone's screen is studied. Based on that, the model of the screen is given for the purpose of antenna designing. Then, PIFA and monopole antenna are investigated for the screen's effect on the antennas with different spacing. At last, the reasons are given for such influence.

Near-Field RCS for Automotive Radar Applications

Abstract: With the growing effort to improve road safety, an accurate characterization of the automotive targets is important. Automotive radar is one of the sensors among others that help detect and identify targets. This paper introduces a method of calculating the radar cross section (RCS) of any arbitrary complex target at near field range; also known as, “near-field RCS” (NF-RCS). In this paper, near-field RCS is calculated not only as a function of range but also as a function of aspect angle. Computational electromagnetic methods are used to calculate the near-field RCS of a metal plate and a vehicle as targets. The use of simulation to calculate near-field RCS improves the design process, reduces testing time and cost.

Novel Integrated Design of a Dual-Band Dual-Polarization 5G mm-Wave Antenna Array Fed by FPCs with a U-Slotted Full-Metal Case for a Cellular Phone

Abstract: A novel design of a dual-band dual-polarization millimeter-wave (mm-Wave) antenna array fed by a flexible printed circuit (FPC) integrated into a full-metal casing with U-shaped slots of a cellular phone for the fifth generation mobile communications (5G) is proposed. This integrated and conformal design is also promising to the future potential attractive antenna solution of mm-Wave antennas in non-mm-Wave antennas (AiA) especially when a metal frame or a metal casing is applied to the exterior of a cellular phone. The novel mm-Wave antenna array is based on 5 dual-band dual-polarization stacked patch antennas embedded in the metal exterior and the antenna array is fed by one FPC with 10 traces for dual polarizations of each antenna element. Owing to the ground shading of the recessed metal cells for the stacked patch antennas, the performance of the antenna array will be not so susceptible to the components or structures behind the integrated metal structures. Bases on simulations, in terms of the input reflection coefficients| S nn | ≤ -10 dB, the bandwidths of the ports (V-ports) in the mm-Wave antenna array for the vertical polarization (V-pol.) range from 27.43 GHz to 28.49 GHz and from 36.29 GHz to 40.05 GHz, respectively; similarly, the bandwidths of the ports (H-ports) in the mm-Wave antenna array for the horizontal polarization (H-pol.) range from 27.36 GHz to 28.46 GHz and from 36.64 GHz to 41.71 GHz, respectively. In other words, the two popular 5G mm-Wave bands of n261 (27.5-28.35 GHz) and n260 (37.0-40.0 GHz) in the third generation partnership project (3GPP) therefore can be accommodated. The maximum (max.) V-pol. peak realized gains in the low band (band n261) and high band (band n260) are 10.10 dBi and 11.21 dBi, and the max. scanning angles are both 45°. Similarly, the max. H-pol. peak realized gains in the low band and high band are 10.26 dBi and 10.57 dBi, and the max. scanning angles are 60° and 30°, respectively. The antenna array also can achieve right-hand and left-hand circular polarizations.

Range Optimization for DSRC and 5G Millimeter-Wave Vehicle-to-Vehicle Communication Link

Abstract: The Dedicated Short Range Communications (DSRC) band (5.85-5.925 GHz) allocated for vehicle-to-vehicle (V2V) communication provides limited opportunities for high speed data transfer. Alternatively, high speed communication of at least 1Gbps is possible in the millimeter-wave (mm-wave) bands. To overcome the propagation losses associated with mmwave frequencies, high gain radio architectures are required. In this paper, we present a novel dual-band V2V receiver architecture for both DSRC and 28GHz communications. For each band, we optimized antenna gain and number of elements to maximize range and data rate. For simplicity, free space path loss model was used for link budget estimation. Results show that an antenna array of at least 9×9 element is required to achieve a maximum data rate of 27Mbps at 5.9GHz and a range of 867m. At 28GHz, the same 9×9 dual band array is capable of transmitting high speed signals at a rate of 1Gbps with coverage of 688m.

Revolutionizing the development of Wearable Antennas

Abstract: This review paper focuses on recently published wearable antenna technologies. The body-worn antennas are essentially any antenna being part of human body clothing. They are specifically used for high flexibility and efficiency communication purposes. Therefore, this study reviews the main technological advances and contributions in the field of wearable antennas for wireless body sensor network (WBSN) applications. This can include the detection of the body when exercise, the monitoring functions such as health care services and for general network connection.

SAR Reduction for an Implantable Antenna Using Ferrite Superstrate

Abstract: Specific Absorption rate (SAR) is one of the most important aspects of biomedical implantable antenna system. It provides the measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field. Despite of having the hazards of damaging human tissues due to power absorption and heating, the implantable antennas are of utmost necessity for recent bio-telemetry applications. Hence, the challenge is to reduce the SAR without affecting the normal antenna parameters and effectively keep it inside an IEEEC9S.1-1999 specified value (1.6 W/Kg for 1 g tissue model). In this paper by using a ferrite sheet we have significantly reduced SAR value of an implantable monopole antenna. By this technique about 42% reduction of SAR value has been achieved without compromising the other antenna parameters.

Influence Analysis of Popular Dielectric Materials for Cellular Phones on 5G mm-Wave Antenna Performance

Abstract: The influences of popular dielectric materials, such as plastic, glass, and ZrO 2 ceramic, for cellular phones on the fifth generation mobile communications (5G) millimeterwave (mm-Wave) antenna performance are analyzed and compared in this study. A 28-GHz 2 × 2 mm-Wave non-stacked patch antenna array is designed on a dielectric substrate to serve the performance baseline. In addition to the mentioned three materials, various material thicknesses and various gaps between the materials and the patch antenna array are also simulated to enable quick understanding of the dielectric material influences on the mm-Wave antenna performance. Based on the simulated results, due to the different levels of dielectric constants, the ZrO 2 ceramic influences the antenna performance most and the plastic influences the antenna performance least. Additionally, when the dielectric material thicknesses are close or equal to integer multiples of 0.5 guided wavelength (λg), the mm-Wave antenna performance in the material-loading scenarios is closer to that in the free space (FS); in other words, the radome influences caused by the materials can be relieved and the gap effects between materials and the antenna array can also be mitigated so that better antenna performance can be attained. The analysis results can also be extended to the radome designs and applications for Terahertz (THz) antenna arrays.

Design of 28 GHz 64-QAM Digital Receiver

Abstract: This paper presents a MIMO+beamformer architecture for millimeter-wave (mmW) 5G wireless applications. A 64-QAM digital receiver operating at 28 GHz is designed for eventual applications in orthogonal frequency division multiplexing (OFDM) 5G links. The receiver design employs a 32-element linear array, with 850 MHz bandwidth sufficient to support 512-point OFDM modulation. The proposed RF chain is aimed at establishing a wireless communication link with a bit error probability better than 10−5. A design procedure is adopted to provide the required signal to noise ratio (SNR) at the input of the digital demodulator. A link budget and noise analysis has been conducted using AWR Microwave Office to evaluate the system's performance under circuit non-idealities and RF impairments, such as noise, distortion, and mismatch. The 64-QAM constellation is simulated for non-ideal conditions using manufacturer test-data and circuit parameters that are embedded into the AWR Microwave Office model. This paper presents the simulation of a single receiver. Physical implementation, measurement, verification, and extension to OFDM based 32-element beamforming arrays is reserved for future work.

Broadband Millimeter-Wave SIW Cavity-Backed Slot Antenna for 5G Applications Using Machine-Learning-Assisted Optimization Method

Abstract: A novel broadband substrate integrated waveguide cavity-backed slot antenna for 5G millimeter-wave wireless applications is proposed. This new antenna topology with constrained footprint achieves great bandwidth enhancement compared with previously proposed designs, by introducing multi-mode operation using loaded cross-shaped slot and unbalanced metallic vias. Moreover, a new machine-learning-assisted optimization method with additional feature is proposed to optimize antenna parameters. The above mentioned design-optimization procedure yields an antenna with measured fractional impedance bandwidth of 23.7%. The measured maximum gain of the antenna is 7.4 dBi within the entire bandwidth.

Compact On-Body Antennas for Wearable Communication Systems

Abstract: This paper presents performance analysis of compact on-body antennas over a female body phantom. These antennas are designed to operate in 2.4GHz industrial, scientific and medical (ISM) band. In the design process, full ground plane is used to minimize radiation towards the body as they are intended to operate in near-body scenarios for Wireless Body Area Networks (WBANs). They offer significant advantages of compactness, light weight, wide radiation pattern over the body surface to provide maximum coverage, and less sensitivity to the variation of the gap between the antenna and the human body. These advantages make them of high interest for on-body communications and wearable applications. Results show that these antennas have good performance and successfully communicate under various near-body scenarios.

Cooperative Transmission in Three-Coil Inductive Power Transfer System with Load-Independent Output Voltages

Abstract: This paper presents cooperative transmission of relay coil in three-coil inductive power transfer systems. In the proposed system, relay coil not only supports primary coil to enhance power transmission distance to secondary one but also plays a role of a receiver providing load-independent output voltage. Compensation schemes of series, capacitor-inductor-capacitor and series are applied for primary, relay and secondary coils to keep output voltages provided by secondary coil as well as by relay coil constant against load resistances. Theoretical analysis is followed by simulations to verify effectiveness of the proposed system.

Reconfigurable and Adaptive Coupled Relay Resonator Platform for a Moving Receiver

Abstract: Linearly arranged passive relay resonators have been shown to be able to extend wireless power transfer range. However, extending this relay concept to a 2-D planar array with the intention to cover a larger area presents challenges; naively constructing a plane of tessellated relays results in a poor efficiency of power transfer due to complex interactions between relays as the number of relays increases [1]. In this paper, we implement the first electronically reconfigurable relay transmitter system, which allows efficient transfer in large relay arrangements and can track a moving receiver across its coverage area. We propose a receiver tracking method and algorithm which can scan the entire coverage area over 2000 times per second and, once found, can configure the relay array to efficiently deliver power to the receiver.

Phased Array Antenna with Key Shaped Elements for 60 GHz mmWave Communications

Abstract: The main focus of this paper revolves around analyzing and simulating an array of antenna with changing phases. Creating the array of antennas helped with increasing the gain and directivity as well as reducing side lobes compared to a single element antenna. The results indicate that steering the beam of the antenna array in a particular direction with the help of phase shifters is much more efficient in comparison to the conventional method of using mechanical modes. On a final note, instead of using a conventional microstrip square patch array element, a new and unique key shaped antenna element has been developed that gives substantially better performance than the original conventional array. The design was targeted to operate at 60 GHz for the purpose of vehicular application.

Impact of Internal Resistances on Performance of Receiver-Side Compensation Circuit for Inductive Power Transfer Systems

Abstract: A compensation circuit comprising of only capacitors at the receiver-side has been proposed to mitigate the no-load current in inductive power transfer systems where the transmitter is compensated by a series capacitor. It has been shown that this receiver-side compensation method features load-independent constant voltage if internal resistances of the coils are negligibly small. In this work, we investigate the impact of internal resistances to provide further insights into the behavior of this method under practical conditions. Our analysis and simulation results show that even under the impact of internal resistances constant voltage functionality can also be achieved, however” at sufficiently large value of the load resistance.

Compact Meta-Surface Antenna Array Decoupling (MAAD) Design for Tightly Coupled Antennas

Abstract: This paper introduces a series of antenna array decoupling method named Meta-surface Antenna Array Decoupling (MAAD) Method. It has two forms: meta-cover and meta-ground, which place sub-wavelength resonators above and below an antenna array, respectively. By properly adjusting the working frequency of the sub-wavelength resonators, the distance between the antenna array and the meta-surface as well as the self-matching of each antenna array elements, the method can significantly reduce the mutual coupling between the element in an array, while maintain or even increase its matching bandwidth. Thanks to the periodic nature of the meta-surface, the method can directly extended to antenna arrays with more than two elements. It can find good application scenarios in both mobile terminals and Massive MIMO base stations of 5G wireless communication systems.

A Circularly Polarized Metasurface Antenna Comprising Rectangular Loops with Gaps for GNSS Receivers

Abstract: The demand for Global Navigation Satellite Systems (GNSSs) has increased. In this paper, a circularly polarized metasurface antenna comprising rectangular loops with gaps for GNSS receivers in the L1 band is proposed. A loop-type Frequency Selective Surface (FSS) is adopted to lower antenna height and enhance antenna gain. The Voltage Standing Wave Ratio (VSWR) bandwidth (≤2) for the proposed antenna is 20.7%. The Axial Ratio (AR) bandwidth (≤3 dB) for the proposed antenna is 18.6%. The proposed antenna achieves broadband VSWR and AR frequency characteristics with a single feed and the antenna height of 0.10 wavelengths. The proposed antenna is suitable for GNSS receivers due to its low profile structure.

Biocompatible Antennas for Implantable Biosensor Systems

Abstract: This paper presents a biocompatible antenna for a subcutaneous implantable biosensor. With the large number of Americans who manage chronic diseases, biosensors offer the capability for better management of these diseases. For diabetes, particularly, the most common monitoring system used is a blood finger pricking system only offers snapshots of blood glucose levels and not trends of glucose changes. These limitations yield a demand for a monitoring system that can provide continuous data streams of glucose levels for better dietary and medicinal regimens. Fully implantable systems offer continuous monitoring while not sacrificing normal daily activities that implantable sensors with an external transmitter can pose. One bottleneck is the miniaturization of telecommunication system. Current implantable devices use the MedRadio band, which offer a challenge for antenna miniaturization for subcutaneous implantation. Additionally the use of copper as the radiator is a challenge due to biocompatibility. As a result there is a need for an implantable antenna that utilizes biocompatible materials, such as Titanium Nitrite (TiN). This paper presents the design and fabrication of a TiN antenna for subcutaneous implant operating in the 2.4 GHz ISM band. The simulation and in vivo test data are presented.

Miniaturization of a Monopolar Wire-Plate Antenna Using Magneto-Dielectric Material

Abstract: This article details a miniaturization strategy for an electrically small Monopolar Wire-Plate Antenna (MWPA) loaded by Magneto-Dielectric Material (MDM). This approach consists in multiplying the number of antenna's short-circuit wires in order to magnify the interaction with the material. A model showing the equivalence between a single-shorted MWPA and n-shorted wires is proposed to serve this strategy of miniaturization.

Passive Interference Cancellation in a 2×2 STAR MIMO Antenna Network

Abstract: Passive cancellation of self-interference and cross-interference is examined under simultaneous transmit and receive (STAR) operation in a 2×2 multiple-input multiple-output (MIMO) node. Circularly-polarized antennas are connected to balanced feed networks for cancellation of the cross-interference created by the antenna-to-antenna coupling between the pair of transceiver antennas. A feedforward path connected between two transceivers in the MIMO node further improves the cancellation of the cross-interference. Measurement results from a two-antenna system with balanced feed networks show a total self-interference cancellation of over 40 dB and cross-interference cancellation of over 46 dB.

Design of a Compact Monopole On-Chip Antenna for 24 GHz Automotive Radar Application

Abstract: This article demonstrates the design of a miniaturized, ultra-wideband monopole on-chip antenna for automotive radar application. The proposed antenna achieves significant impedance bandwidth of 28.4 GHz (S 11 < -10 dB from 8.3 GHz to 36.7 GHz) with centre frequency of 24 GHz. It achieves minimum return loss of around -32 dB at 24 GHz that clearly indicates good impedance matching of the antenna with the source. The proposed antenna offers peak gain of -3 dBi at 28 GHz. Compactness (size of 3.8 mm × 4 mm × 0.676 mm) and simple design layout is the main attractiveness of this research work. The 3D antenna structure has been analyzed using ANSYS HFSS v17. Silicon wafer with thickness of 675 µm is used as a substrate of the proposed antenna.

High Bitrate Data Transmission Using Polypropylene Fiber in Terahertz Frequency Range

Abstract: We present the experimental demonstration of real-time data transmission using long subwavelength dielectric fiber in the Terahertz (THz) frequency range. A commercial filament made of polypropylene material with the diameter of 1.75 mm is used as the solid core fiber for signal transmission. A photonics-based THz communication system operating at the carrier frequency of 140 GHz is used to characterize the fiber. The fiber is butt coupled at both emitter and detector antenna to minimize the free space coupling loss. The performance of the fiber is measured by recording the bit error rate (BER) for the transmitted data rate of 5 Gbps with a pattern length of 231-1. BER of 10−7 is recorded for the fiber length of 3 m and 5 m respectively at the emitter photocurrent value of 8 mA. Finally, an error free data transmission using a 1 m fiber with the diameter of 670µm is demonstrated successfully.

Reconfigurable Terahertz Array Antenna

Abstract: Terahertz imaging with high speed acquisition and spatial resolution is desired in many practical applications. In this work, a proof of concept for high speed near-field imaging with sub-wavelength resolution using spatial light modulator is presented. An 8 channel THz detector array antenna with an electrode gap of 100 µm and length of 5 mm is fabricated using the commercially available GaAs semiconductor substrate. Each array antenna can be excited simultaneously by spatially reconfiguring the optical probe beam. The detected spatial THz electric field can be recorded using 8 channel lock-in amplifiers. By scanning the probe beam along the length of the array antenna, a 2D image can be obtained with amplitude, phase and frequency information. The time taken to reconstruct the image is limited only by the speed of the delay line to record the THz pulse at each spatial location.

A Thin Wideband Radar Absorber Based on a Dual-Substrate FSS with Quadruple Hexagonal Split Rings for Stealth Aircraft Application

Abstract: Radar absorbing material is an indispensable part of a stealth aircraft. It renders the aircraft invisible to radar detection. This paper proposes a wideband dual-substrate frequency selective surface based on quadruple hexagonal split rings as a radar absorber. Such split rings on Rogers RT-5880 constitutes a passband characteristic while ECCOSORB© SF with copper patch acts to reduce the transmission. The 90% absorption bandwidths are 5.15 and 4.70 GHz in the X-band for TE & TM modes, respectively, at normal incidence. The absorption remains as high as 90% for an incident angle of upto 45°, beyond which the absorption drops slightly to about 80% while the bandwidth is slightly reduced.

Experimental Results of Interference Mitigation Using Ultra-Wideband Spreading

Abstract: We present measurement results for a novel ultrawideband (UWB) low-cost transmit/receive architecture with reduced power and hardware requirements that includes interference mitigation and accommodates multiple users. Specifically, hardware prototype is presented with measurements. To assess the systems performance and impact of the spreading/despreading process, a noise analysis conducted for the transmitter and receiver chains. Specifically, Bit-Error-Rate (BER) curves are generated from an Over-the-Air (OTA) communication link showing interference-to-signal ratios (gain margin) improved by at least 16 dB.

A New Method to Reduce the Impact of the Common Mode Currents for Field Measurements on Symmetrical Antennas

Abstract: Common mode currents on the feeding line may significantly impact on antenna radiation measurements. In this paper, we propose a novel technique to discriminate antenna radiation from the total field produced by the antenna-feeder set. Our method is based on averaging a normalized, magnetic field measured at different distances away from the antenna under test. The common mode current has a fluctuating contribution that cancels out in the average figure. The proposed approach was validated by measuring a symmetrical dipole fed through a coaxial cable; the probe antenna was a small square loop.

Characteristic Mode Analysis of U-Shaped Folded Dipole Antenna for WiMAX

Abstract: U-Shaped Folded Dipole Antenna (UFDA) have been proposed for WiMAX. UFDA element is placed on the ground plane so that the occupied volume of the UFDA element is reduced as much as possible. In this paper, Characteristic Mode Analysis (CMA) is used for the analysis of UFDA, which is composed of UFDA element and the ground plane. As a result, it is found that two types of modes in the resonance of UFDA occur. The one is the mode of UFDA element and the other is the mode of the ground plane. Two frequency bands of WiMAX can be covered, when the shape of UFDA is adjusted by using the result of CMA.