A four element stringray-shaped MIMO antenna system for UWB applications

This paper presents a CoPlanar-Waveguide (CPW)-fed stingray-shaped Ultra-WideBand (UWB) Multiple-Input–Multiple-Output (MIMO) antenna system designed for microwave imaging applications. Featuring a diagonal square with four inner lines and a vertical line at the center from toe to tip with a CPW feed line, the unit antenna element looks like a stingray fish skeleton and is, therefore, named as a stingray-shaped antenna. It offers a bandwidth spanning from 3.8 to 12.7 GHz. Fabricated on a 31mil RO5880 RF teflon substrate with a relative permittivity of 2.2, the proposed antenna has dimensions of 26 × 29 × 0.787 mm (Formula presented.). The maximum realized gain achieved is 3.5 dBi with stable omnidirectional radiation patterns. The antenna element is used in a four-antenna MIMO configuration with an isolation-improving structure at the center. The MIMO system has dimensions of 58 × 58 × 0.787 mm (Formula presented.) with a maximum realized gain of 5.3 dBi. The antenna’s performance in terms of MIMO parameters like Envelope Correlation Coefficient (ECC) and Diversity Gain (DG) is within satisfactory limits for medical imaging applications. Time domain analysis also yields positive results, allowing its integration into a breast phantom tumor detection simulation. The simulation and measurement results demonstrate excellent agreement, making this antenna a promising candidate for microwave imaging and biomedical applications

A phased array antenna system of a millimeter-wave FMCW radar for blind spot detection of mobile robots

Mobile robots have been extensively used in manufacturing plants for inter-logistic transportation in recent years. This paper covers a phased array antenna design for a millimeter wave radar system to improve lidar-based navigation systems' safety and environmental consciousness. The K-band phased array antenna, when integrated with 24 GHz Frequency-Modulated-Continuous-Wave (FMCW) radar, not only enhances the accuracy of the 2-D Area Scanning lidar system but also helps with the safe operation of the vehicle. The safety improvement is made by covering blind spots to mitigate collision risks during the rotations. The paper first reviews the system-level details of the 2D lidar sensor and shows the blind spots when integrated into a Mobile Robot prototype. Then continues with the inclusion of an FMCW Low-Speed Ramp radar system and discusses the design details of the proposed K-band antenna array, which will be integrated with a radar sensor

FDTD-based SAR calculation of a wearable antenna for wireless body area network devices

Wireless-connected wearable electronics are finding extensive usage for diagnostic and therapeutic purposes after the globally spread pandemic disease of COVID-19. Although they are undoubtedly helpful for keeping physical distance, their health effects are still under investigation from different aspects and are still a concern for the end-users. In this study, a custom M-shaped wearable antenna covering the wireless body area network and wireless local area network frequencies is designed, built, and measured. A beret cap made from a 2 mm thick textile is used as a substrate. The specific absorption rate (SAR) in a realistic human-head model due to electromagnetic energy produced by the antenna is evaluated using the finite-difference time-domain method. The SAR distributions for 1-g and 10-g tissues are calculated at 2.4 and 5.8 GHz. It is shown that the obtained maximum SAR values for 1-g and 10-g tissues at each frequency of interest were less than the limits determined by IEEE RF exposure guidelines and standards

Analysis of a compact multi-band textile antenna for WBAN and WLAN applications

A dual-band wearable antenna is designed on a textile material. The design operates at ISM bands available for Wireless Body Area Network (WBAN) and Wireless Local Area Network (WLAN) with an input match better than -15 dB. The antenna is designed by using Computational Electromagnetic Software (CEMS) based on Finite-Difference Time-Domain (FDTD) method. A three-layer phantom model including skin, fat and muscle has been considered to compute the specific absorption rate (SAR). The maximum value of SAR averaged over 1g and 10g of tissue is less than 1.6 W/Kg and 2 W/Kg, respectively, when the maximum incident power of the antenna is 63 mW. These values are incompliance with the international electromagnetic safety standards

Dual-band multiple-element MIMO antenna system for next-generation smartphones

This work presents a cost-effective multiple-element multiple-input multiple-output (MIMO) antenna system for next-generation smartphones. The proposed antenna system is developed on a 0.8 mm thin FR-4 substrate with a relative permittivity of 4.4, which consists of one main board and two sideboards. The dimensions of the main board and the two side boards are 150 × 75 mm2 and 150 × 6 mm2, respectively. The radiating elements are printed on the sideboards to provide space for other radio frequency (RF) components to be embedded on the main board. The proposed antenna resonates at two distinct allotted 5G bands, i.e., 3.5 GHz and 5.4 GHz, with impedance bandwidths of 200 MHz and 700 MHz, respectively. The isolation between the antenna elements is noted to be >18 dB and >12 dB for the 3.5 GHz and 5.4 GHz frequency bands. In addition, the proposed MIMO antenna provides pattern and spatial diversity characteristics in both bands with good gain and efficiency. Furthermore, the MIMO parameters such as envelope correlation coefficient (ECC), mean effective gain (MEG), and channel capacity (CC) are calculated, and it is observed that the MIMO antenna offers good diversity performance for the bands of interest. A prototype is fabricated and measured to verify the numerical data. The simulated results were discovered to be in excellent agreement with the measured results. It is also observed that the proposed MIMO antenna system holds promising features, and can be utilized for future generations of smartphones.Princess Nourah bint Abdulrahman Universit

mmWave polarization diversity wideband multiple-input/multiple-output antenna system with symmetrical geometry for future compact devices

The fifth generation (5G) of mobile networks is a significant technological advancement in telecommunications that provides faster data speeds, lower latency, and greater network capacity. One of the key technologies that enables 5G is multiple-input/multiple-output (MIMO) antenna systems, which allow for the transmission and reception of multiple data streams simultaneously, improving network performance and efficiency. MIMO is essential to meeting the demand for higher data rates and improved network performance in 5G networks. This work presents a four-element MIMO antenna system dedicated to the upper 5G millimeter-wave (mmWave) spectrum. The suggested antenna system is designed using an ultra-thin RO5880 substrate having total dimensions of 20 x 20 x 0.254 mm(3) with symmetrical geometry. The proposed antenna covers a fractional bandwidth of 46.875% (25-38 GHz), covering potential 5G bands of 26, 28, and 32 GHz, and offers isolation of >18 dB. The proposed MIMO system is fabricated and tested in-house. The antenna showed efficiency >88% at the potential band of interest and a peak gain of 3.5 dBi. The orthogonal arrangement of the resonating elements provides polarization diversity. Also, the MIMO parameters obtained, such as mean effective gain (MEG), envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and total active reflection coefficient (TARC), are found to have good performance. The measured results obtained are found to be in good agreement with simulations, hence making the proposed MIMO antenna suitable for handheld mmWave 5G devices.Prince Sultan University, Riyadh, Saudi Arabi

Numerical and measurement based modeling of a MiM capacitor in a 0.25 µm SiGe-C BiCMOS process

This study presents the generation of a scalable model based on measurement-aided numerical calculations for MiMCap (Metal-Insulator-Metal Capacitor) structures with a 0.25 µm SiGe-C BiCMOS technology. Various MiM capacitor structures with several different areas and peripheral sizes are fabricated in an in-house developed BiCMOS process. A set of fix-size models and a generic, scalable model are developed based on numerical EM calculations. The validity of the constructed model is verified with the measurement results. The model includes the breakdown voltage ratings, which are also extracted through the measurements. The model, EM simulations, and measurement results are in good agreement

A wideband high-efficiency doherty power amplifier for LTE

This article describes a broadband Doherty power amplifier designed with a class AB and class C PA that is suitable for LTE Band-7 and Wi-Fi applications. The output matching network is theoretically analyzed, with emphasis on the effect of the auxiliary amplifier's non-ideal infinite output impedance on parasitic devices. A novel Doherty-like power amplifier (DPA) is constructed with 25 W, 2.2-2.8 GHz GaN HEMT transistors. The quarter-wave transformer that was previously used in the DPA topology was replaced by the corresponding Klopfenstein tapper network. Real-world prototype implementations have shown that this modification increases the achieved DPA bandwidth (BW) compared to conventional topologies while maintaining efficiency values. (Fractional bandwidth equals 24%) The DPA assumes an OBO value of 6 dB, which is typical for basic designs and explanations because the voltage level involved is 1:4 and the peak power amplifier is activated at half of the input voltage's dynamic range. However, in order to increase the OBO value, the signal must first be compatible with the PAPR value. This can be accomplished by adjusting the power divider in an asymmetrical manner. The OPBO range was extended using the asymmetric DPA technique

Compact wide-band gysel power divider

A compact and wideband Gysel power divider is proposed in this study. The design steps on a widely available low-cost FR-4 substrate are presented. The design is simulated with a Method-of-Moments based 2.5D EM simulator and verified with measurement results. The power divider supports an operating bandwidth of 1.5 GHz between 1.94 GHz and 3.44 GHz. The measurements show an insertion loss of 4.5 dB and return loss better than 15 dB which agrees with simulations. The fabricated circuit has at least three-fold wider bandwidth (with %56 fractional bandwidth) and four-fold smaller size (3.6 cm x 4.3 cm) than similar designs in the recent literature

6 GHz low noise amplifier design with 65nm CMOS for 5G/6G applications

It is envisaged that 6G network technology will be popular due to its higher working frequencies than 5G networks, and this will ensure higher data rates, greater capacity and lower latency. 6G mobile technology will support sub-microsecond delays which makes communication almost instantaneous. Realization of these goals depend on faster circuits with low noise levels in both transmitters and receivers. In this work, a low noise amplifier (LNA) was designed in 65nm UMC CMOS technology with Cadence Spectre. Differential common source topology with integrated inductors were utilized to achieve low differential noise and better matching performance with higher gain. Proposed LNA has 20dB gain at 6GHz, and the gain is higher than 13dB from DC to 8 GHz. Minimum noise figure is 2.24 dB and S11 is -30dB at 6GHz. Simulated IIP3 is -6.5dBm. The design works with 3.6 mA total current from 1.2V supply voltage