Effective Isotropic Radiated Power Research Articles

A Deep Learning Framework for Evaluating the Over-the-Air Performance of the Antenna in Mobile Terminals.

This study introduces RTEEMF (Real-Time Evaluation Electromagnetic Field)-PhoneAnts, a novel Deep Learning (DL) framework for the efficient evaluation of mobile phone antenna performance, addressing the time-consuming nature of traditional full-wave numerical simulations. The DL model, built on convolutional neural networks, uses the Near-field Electromagnetic Field (NEMF) distribution of a mobile phone antenna in free space to predict the Effective Isotropic Radiated Power (EIRP), Total Radiated Power (TRP), and Specific Absorption Rate (SAR) across various configurations. By converting antenna features and internal mobile phone components into near-field EMF distributions within a Huygens' box, the model simplifies its input. A dataset of 7000 mobile phone models was used for training and evaluation. The model's accuracy is validated using the Wilcoxon Signed Rank Test (WSR) for SAR and TRP, and the Feature Selection Validation Method (FSV) for EIRP. The proposed model achieves remarkable computational efficiency, approximately 2000-fold faster than full-wave simulations, and demonstrates generalization capabilities for different antenna types, various frequencies, and antenna positions. This makes it a valuable tool for practical research and development (R&D), offering a promising alternative to traditional electromagnetic field simulations. The study is publicly available on GitHub for further development and customization. Engineers can customize the model using their own datasets.

A Single-Board Integrated Millimeter-Wave Asymmetric Full-Digital Beamforming Array for B5G/6G Applications

In this article, a single-board integrated millimeter-wave (mm-Wave) asymmetric full-digital beamforming (AFDBF) array is developed for beyond-fifth-generation (B5G) and sixth-generation (6G) communications. The proposed integrated array effectively addresses the challenge of arranging a large number of ports in a full-digital array by designing vertical connections in a three-dimensional space and successfully integrating full-digital transmitting (Tx) and receiving (Rx) arrays independently in a single board. Unlike the traditional symmetric array, the proposed asymmetric array is composed of an 8 × 8 Tx array arranged in a square shape and an 8 + 8 Rx array arranged in an L shape. The center-to-center distance between two adjacent elements is 0.54λ0 for both the Tx and Rx arrays, where λ0 is the free-space wavelength at 27 GHz. The proposed AFDBF array possesses a more compact structure and lower system hardware cost and power consumption compared with conventional brick-type full-digital arrays. In addition, the energy efficiency of the proposed AFDBF array outperforms that of a hybrid beamforming array. The measurement results indicate that the operating frequency band of the proposed array is 24.25–29.50 GHz. An eight-element linear array within the Tx array can achieve a scanning angle ranging from −47° to +47° in both the azimuth and the elevation planes, and the measured scanning range of each eight-element Rx array is –45° to +45°. The measured maximum effective isotropic radiated power (EIRP) of the eight-element Tx array is 43.2 dBm at 28.0 GHz (considering the saturation point). Furthermore, the measured error vector magnitude (EVM) is less than 3% when 64-quadrature amplitude modulation (QAM) waveforms are used.

Microstrip antenna with reflector and air gap for short range communication in 900 MHz band

This paper proposes a microstrip antenna that was made of a microstrip fed slot with a complimentary stub on a single dielectric medium. This antenna was integrated with a reflector and air gap for the application of short range communication (SRC) in a 900 MHz band. Analyses were made on the dimension of the reflector and the height of the air gap towards the antenna performance. Besides, an antenna field test was done for the propagation distance of the proposed antenna. As a result, with the antenna size of 13,770 mm2 , the measured return loss was -10.79 dB and the directivity gain was 7.44 dBi. Besides, with the effective isotropic radiated power (EIRP) of 7.44 dBm, it was predicted that at 100 m, the received signal would be around 60 to 70 dBm. Therefore, a high gain was produced by using a reflector with air gap and a compact size was achieved if compared to conventional high gain antenna designs such as Yagi Uda. Thus, it is suitable for a communication device such as the SRC application.

Characterizations for eWLB (Embedded Wafer Level Ball Grid Array) Antenna in Molded Package Integrations in 77GHz Automotive Applications

The worldwide IC market has had a significant growth rate in recent years, driving diversified package solutions in the segments of communication, computing, consumer, automotive, industrial, etc. Among these market segments, the automotive market is forecast to have the strongest CAGR (Compound Annual Growth Rate) of any of the end-use segments in the next 5 years, which results in more IC packages and components being designed into automotive vehicle systems such as infotainment, ADAS (Advance Driving Assistance System), instrumentation, body systems, battery control systems and so on. In these applications, the 77GHz short-range radar sensor application that can enable higher EIRP (Effective Isotropic Radiated Power) and adaptive cruise control performance has become more attractive to be commercialized. Due to the benefits of shorter interconnection length, lower conductive loss with smooth Cu surface as well as a lower dielectric constant and dielectric loss of materials in a fan-out wafer level package (FOWLP) technology, the FOWLP is proven as a suitable packaging solution to achieve the high speed and frequency requirements in 5G and mmWave applications. The eWLB Embedded Wafer Level Ball Grid Array) is a versatile FOWLP technology, providing a robust package platform in a space-efficient design with the very dense interconnection and routing of multiple dies as well as a smaller footprint and lower package profile providing a reliable package solution. Meanwhile, since the utilization of an antenna that is integrated into the packages has been studied as a lowcost solution because the packages can be tested in normal FR4 printed circuit board (PCB) instead of the RF function integrated PCB, the eWLB integrated with molded antenna chip packages (called eWLB antenna in molded package) technology is introduced in this paper. The characterizations for assembly process challenges are evaluated and illustrate the process optimizations of equipment handling, antenna molded chip package fabrication, reconstitution process control and warpage characterization of the molded wafer. In addition, the radio frequency (RF) test validation is performed to verify the performance of scattering parameter (S-parameter), radiation pattern, impedance and detection range of the antenna. In order to prove the reliable quality and yield of the evaluated eWLB antenna in molded packages, package-level reliability tests are studied. Through these results, it will show that this eWLB antenna in molded package integration is a robust and costeffective solution for 77GHz automotive applications.

A development of mobile application satellite link budget calculator – SATELEC

Link Budget is a calculation of gains and losses during transmission from transmitter to receiver in each communication system. In satellite communication, the main purpose of calculating link budget is to analyse the satellite system performance. One of the parameters to measure the satellite link performance is the Carrier to Noise ratio (C/N). There are a few satellite link calculators were developed using MATLAB/GUI and website. However, there are no available apps to help student to compare the calculated satellite link budget calculator for self-study. Therefore, a mobile apps called SATELEC was developed to calculate satellite link budget parameters. By using this satellite link budget calculator apps, all parameters such as Effective Isotropic Radiated Power (EIRP), Power Flux Density, Path Loss, Antenna Gain and Power Received can be calculated. After the value of power received is obtained, the value of Carrier to Noise ratio (C/N) can be determined by taking into account the noise in the communication. Results shows values obtained from the mobile is reliable after comparison with calculated value.

A High-Efficiency High-Power 170-176-GHz Frequency Stabilized Quadrature Radiator

In this article, we present a high-efficiency high-power radiator with on-chip frequency stabilization and quadrature generation capabilities for short-coherence-time imaging and wireless communication applications. To achieve efficient sub-terahertz (sub-THz) signal generation, a systematic design approach using the device-centric gain-plane optimization is employed. In addition, an on-chip frequency stabilization mechanism utilizing the inherent power level variation over the tuning range is proposed. To show the feasibility of this approach, a 170–176-GHz radiator prototype is demonstrated, which has an effective isotropic radiated power (EIRP) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+$</tex-math> </inline-formula> 24.6 dBm and a dc-to-RF efficiency of 9.2%. The prototype is fabricated in a 55-nm SiGe bipolar complementary metal–oxide–semiconductor (BiCMOS) process and achieves one of the highest output power and dc-to-RF efficiency among designs beyond <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{\text{max}}$</tex-math> </inline-formula> /2. The frequency stabilization mechanism reduces the long-term frequency drifts by 4.3 times.

On the Study of Interference Scenario on TV Broadcast and Wireless Systems for Emergency Communication Networks in TVWS

This paper investigated frequency sharing between primary TV systems (channels 32 and 49) and Emergency Communication Networks (ECNs). The networks to be implemented in the Osogbo axis of Osun State function on a secondary geographical basis, creating no harm to the original licensed primary TV viewers. A minimum separation distance of 41 dB was suggested as the protected contour for the UHF spectrum to oversee the protection of primary TV users for the UHF bands under consideration. The effects of changing the secondary systems' transmitting power, transmission frequency, and antenna height on the service coverage distance were also explored. The performance of the UHF band was evaluated when it was utilized for secondary transmission at both low and high transmitting powers, with the performance criterion being percentage coverage distance. This work complies with the International Telecommunication Union-Radio sector (ITU-R) recommendations of 16 dB for signal-to-noise ratio and 41 dB for signal strength. It can also be deduced from the result that when the transmission power of ECN devices is raised from 40 mW to 4 W, Effective Isotropic Radiated Power (EIRP) is used; it caused a 76.19% reduction in the coverage spacing for TV channels of ECN Network secondary devices. For the White Space Device (WSD) to operate in Temporal mode, the maximum allowable power (4 W) used in spatial mode should be replaced by a 76.19 per cent reduction. Additional sensing margins of 3.76 dB and 4.04 dB for channels 33 and 43 must be added to the FCC threshold limit of -114 dBm criterion for TV white spaces to assure ECN deployment without causing severe interference to TV customers.

Validation of GPS III transmit antenna calibrations

Accurate information about the satellite transmit antennas is essential for high-precision GNSS applications. Such metadata of the GPS III satellites were publicly made available by the manufacturer Lockheed Martin. They comprise phase center offsets (PCOs), phase patterns, and directivity patterns. These calibrations are validated with ground-based measurements of a global GPS tracking network and observations of a high-gain antenna. Phase center offsets and patterns are estimated from dual-frequency observations of a ground tracking network. The ionosphere-free L1/L2 z-PCOs show a 10 cm offset w.r.t. the manufacturer calibrations due to already known inconsistencies with the ITRF2020 scale fixed in the estimation. The standard deviation of the differences between estimated and calibrated z-PCOs is 2.7 cm. The estimated phase patterns have a 0.7 mm RMS consistency with the manufacturer calibrations after minimizing the raw patterns for nadir angles between 0° and 14°. The directivity patterns are validated with the effective isotropic radiated power (EIRP) measured with a 30 m high-gain antenna. The measured EIRP for the L1 and L2 band is affected by M-code transmission from a distinct antenna. When modeling the additional contribution of this antenna, the nadir-angle variation of the EIRP matches the calibrated directivity patterns with a precision of 0.1 dBW. Representative transmit power values of the main navigation antenna amount to 125 W, 30 W, and 85 W in the L1, L2, and L5 bands, while the L1 and L2 M-code signals are transmitted with about 30 W and 25 W, respectively.

A 223–276-GHz Cascadable FMCW Transceiver in 130-nm SiGe BiCMOS for Scalable MIMO Radar Arrays

This article reports a 223–276-GHz monostatic frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) chip. The TRX is suitable for building massive multiple-input multiple-output (MIMO) radar arrays in the daisy-chain topology because of its cascadable feature based on the injection-locking feedthrough technique. The TRX is based on 18 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> frequency multiplication chain that can be fed by either an external signal generator (SG) or its internal voltage-controlled oscillator (VCO). The modulation bandwidth (BW) is about 53 GHz when the internal VCO is activated, resulting in a range resolution of better than 3 mm. The peak output power is 3.1 dBm at 240 GHz with a 3-dB BW of 41 GHz. Its receiver (RX) channel is based on the in-phase/quadrature architecture enabling complex signal sampling. The minimum single-sideband (SSB) noise figure (NF) is 18.7 dB at 255 GHz, and the average value is 20.7 dB. The TRX chip includes an on-chip antenna coupled with a silicon lens, offering a peak effective isotropic radiated power (EIRP) of 27 dBm at 240 GHz. The TRX consumes a dc current of 234 and 270.1 mA from a single supply voltage of 3.3 V for external and internal VCO operations, respectively. The chip occupies a total area of 2.7 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (2.16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 1.26 mm).

Scalable 3-D-Printable Antenna Array With Liquid Cooling for 28 GHz

This paper presents a scalable and compact 3D-printed Vivaldi antenna array with liquid cooling for the frequency band from 24.0 to 29.5 GHz. The proposed design consists of an 8 × 8 antenna array with commercial beam-forming ICs on the antenna-side of the PCB for efficient PCB area utilization and that enables a high integration level. Scalable liquid cooling is integrated into the 3D-printed antenna array. The measured temperature with water cooling during operation remains below 50°C. The simulated total active reflection coefficient of the unit cell is lower than -9.6 dB for beam steering angles up to 57° from the broadside. The effective isotropic radiated power (EIRP) of the prototypes is up to 59.7 dBm.

Three‐state pattern reconfigurable active antenna integrated with Gunn oscillator and switched‐line phase shifter

AbstractIn this paper, a novel active integrated array antenna (AIAA) is introduced for the purpose of enabling pattern switchable functionality. The AIAA includes a Gunn oscillator, four microstrip antennas, and two switched‐line phase shifters. The Gunn oscillator provides high‐output RF power to excite the antenna elements through the switched‐line phase shifters. The switched‐line phase shifter allows for switching the main beam direction of the radiation pattern among three states, specifically , and in the ‐plane without shifting its high resonance frequency. Besides, the AIAA requires fewer RF switching diodes in a compact, cheap, and simple layout when compared to previously reported AIAAs. An experimental evaluation of the proposed antenna's performance is conducted and the results indicate an effective isotropic radiated power (EIRP) of +16.09 dBm at the frequency of 9.41 GHz. In all three states, the cross‐polarization suppression is better than 15 dB.

Array Calibration and Digital Predistortion Training Using Embedded Near-Field Feedback Probes and Orthogonal Coding for Enhancing the Performance of Millimeter-Wave Beamforming Arrays

This letter proposes an active array calibration and digital predistortion (DPD) training method that relies on a series of measurement data captured using near-field (NF) probes embedded within the array to enhance the performance of millimeter-wave (mm-wave) radio frequency (RF) beamforming arrays. These measurements are obtained using phase settings that are based on orthogonal coding to enable the characterization of the linear and nonlinear errors in the array’s RF chains. The use of embedded NF probes in the proposed method makes it suitable for infield testing. Specifically, the proposed theory is formulated to allow for beamforming-phase-dependent error calibration as well as array linearization without resorting to element-wise measurement or far-field (FF)-based feedback. Furthermore, the proposed theory does not impose a flat coupling requirement between the NF probes and the array antenna elements. Experimental results are conducted on a custom-built 16-element RF beamforming array with four embedded NF probes and operated at 37.5 GHz. The measurements revealed that applying the proposed calibration method reduced the imbalance in the radiation pattern side lobes by up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2$</tex-math> </inline-formula> dB and achieved comparable performance to element-wise FF-based calibration. Furthermore, the proposed DPD training method enabled increasing the effective isotropic radiated power (EIRP) from 32 to 34.2 dBm while maintaining an error vector magnitude (EVM) below 3.5%.

A 22–28 GHz Polarization-Reconfigurable Flat-Panel 8 × 8 Tx/Rx Phased Array Antenna With Uniquely Arranged Novel Radiating Elements for CubeSat Communication

In this paper, a wideband (22-28 GHz), polarization reconfigurable, flat panel, 8x8 transmit (Tx)/receive (Rx) phased array antenna (PAA) is proposed. The array offers a realized gain of 22-23 dBi/dBic in the broadside direction and scans to approximately ±50° while maintaining 3dB gain drop/scan loss, low cross-polarized fields, and axial ratio (AR) below 3dB (in case of circular polarization (CP)) over the entire bandwidth within the given scan range. By utilizing the amplitude and phase control mechanism of the Radio Frequency Integrated Circuits (RFICs) employed for the beamforming network (BFN), each single radiating element of the array can work in four polarization cases such as horizontal (X-), vertical (Y-), left-hand circular and right-hand circular polarizations. The single element is a novel stacked patch configuration with L-shaped stubs at the two opposite corners of the driven patch and stubs on radiating edges of both the driven and parasitic patches. The radiator offers a wideband performance in addition to resolving the poor isolation between the two ports, thereby improving the cross-polarized fields and AR over the entire bandwidth. The radiating elements are arranged in a unique way in the array such that the benefit of element mirroring is achieved during the dual linear cases, whereas the benefit of sequential rotation of elements is achieved in dual CP cases, which further improves cross-polarized fields and AR. The simulated results are validated through the measurement results for a fabricated PAA prototype for the scanned radiation patterns for all four polarizations in receive mode, antenna gain-to-noise temperature (G/T) in receive mode, and effective isotropic radiated power (EIRP) in transmit mode.

A 39-GHz CMOS Bidirectional Doherty Phased- Array Beamformer Using Shared-LUT DPD With Inter-Element Mismatch Compensation Technique for 5G Base Station

This article demonstrates a 39-GHz CMOS phased-array beamformer aiming for power-efficient and area-efficient fifth-generation (5G) dual-polarized multiple-in–multiple-out (DP-MIMO) applications. To address the digital pre-distortion (DPD) implementation issue in the massive beamformer elements with Doherty technique integrated, an inter-element mismatch compensation technique is introduced for improving the shared-lookup table (LUT) DPD performance over the process, voltage and temperature (PVT) variations. A bidirectional Doherty power amplifier (PA)-LNA is proposed to enhance the power back-off (PBO) efficiency regarding the high peak-to-average power ratio (PAPR) 5G signals, meanwhile cost down the system by the unbalanced neutralized bidirectional operation. The proposed phased-array beamformer chip is fabricated in 65-nm CMOS technology and packaged in a wafer-level chip-scale package (WLCSP). Each element occupies only a 0.82-mm2 chip area, including the on-chip low-dropout regulator (LDO). The measured stand-alone Doherty PA-LNA achieves 18.9-dBm saturated output power with 17.8% power-added efficiency (PAE) at 6-dB PBO in PA mode and obtains a 4.8-dB noise figure (NF) at 40 GHz in LNA mode. By utilizing the proposed mismatch compensation, the measured 64-quadrature amplitude modulation (QAM) orthogonal frequency-division multiple access (OFDMA)-mode error vector magnitude (EVM) and adjacent channel leakage ratio (ACLR) with the shared-LUT DPD are improved from −22.4 to −25.0 dB and from −28.7 to −32.1 dBc, respectively. The 64-element module achieves a 55.2-dBm saturated effective isotropic radiated power (EIRP) and supports 21-Gb/s single-carrier (SC) mode data streaming. The measured 64-element transmitter (TX) EVM is −25.2 dB at 43.2 dBm with 3.5-GSymbol/s baud rate in 64 QAM, and the corresponding 64-to-4 elements TX-to-receiver (RX) EVM is −22.5 dB. The consumed power for each element is 402 mW at saturation output point in TX mode and 87 mW in RX mode.

A 28-GHz Four-Channel Beamforming Front-End IC With Dual-Vector Variable Gain Phase Shifters for 64-Element Phased Array Antenna Module

A 28-GHz fully differential four-channel beamforming front-end IC with variable gain phase shifters (VGPSs) is presented, of which orthogonal phase and gain control is achieved in a single block using the proposed dual-vector synthesis technique. This greatly reduces chip size, power consumption, and calibration complexity. The antenna switch embedded in the front-end matching network minimizes degradation of the transmitter (TX) efficiency and receiver (RX) noise figure. The multi-mode power amplifier (PA) with a built-in linearizer is presented to have high efficiency and linearity for all power modes, which reduces power consumption during gain control. Also, a differential four-way power divider and an single pole double throw (SPDT) switch are introduced in the common path, which has a small chip size and a low insertion loss. By adopting differential structures for all components in the four-channel IC, the effect of parasitic grounding inductances due to bonding and package is minimized. Thanks to the proposed dual-vector VGPS, the rms gain error of 0.21 dB and the peak phase variation of ±1.7° are achieved during phase control and gain control, respectively, without any calibration. The four-channel front-end IC also achieves rms phase error of only 1.4° during the simultaneous phase and gain control without any calibration. It has a TX OP1dB of 13.3 dBm and the highest linear output power of 7.2 dBm with 400-MHz 64-QAM fifth-generation (5G) new radio (NR) signals with 9.6-dB peak-to-average power ratio (PAPR). Also, this article presents a 64-element brick-type phased array antenna using four-channel core chips. It shows a high effective isotropic radiated power (EIRP) of 54.4 dBm at 28 GHz. An over-the-air link is demonstrated with a competitive data rate of 4 Gb/s using 64-QAM waveforms over all scan angles at a distance of 100 m.

A first‐harmonic push–push oscillator based active integrated dual‐beam switchable array antenna

This paper proposes a new active integrated array antenna (AIAA) for dual-beam switchable functionality. The proposed AIAA comprises a first-harmonic push–push oscillator, four linearly polarized microstrip antennas, and a switchable feed network. The first-harmonic push–push oscillator eliminates the impact of load variation and usage of a filter to suppress the second- and higher-harmonic frequency signals. By using the switchable feed network, the main beam direction of the radiation pattern can be switched between two states, i.e. θ = ± 10 ∘ $\mathbf {\theta = \pm }10\mathbf {^{\circ }}$ . The performance of the proposed antenna is experimentally evaluated. The measured results show an effective isotropic radiated power (EIRP) of +27.5 dBm, DC-to-RF efficiency of 20.26%, and figure of merit (FOM) of −155.2 dBc Hz−1 at the fundamental frequency of 5.9 GHz.

Focal-Plane Arrays With Improved Scan Capabilities

This article investigates the limits of focal-plane array (FPA) technology by studying a double-reflector antenna system with wide-angle scan capabilities. The proposed reflector configurations are analyzed in terms of effective isotropic radiated power (EIRP) maximization, minimization of the required total number of array elements for a wide-scan range, and the highest number of simultaneously active array elements of the phased-array feed. Presented configurations have capabilities to operate in the scan range up to ± 30° in azimuth (±35 beamwidths scan) and ± 3° in elevation. It has been demonstrated how different optimizations could allow to build systems with varying performance in terms of the key operation parameters, such as array size, EIRP, and the number of active array elements. A detailed analysis is provided that demonstrates the potential applicability of this concept in future millimeter-wave (mm-wave) applications.

Dual-Band 28- and 39-GHz Phased Arrays for Multistandard 5G Applications

This article presents a 32-element 28/39-GHz dual-band phased array for fifth-generation (5G) communication systems. The array is based on separate sets of SiGe transmit/ receive (Tx/Rx) beamformer chips to realize independent dual-beamforming capabilities at orthogonal linear polarizations. The beamformer chips are integrated with an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8 \times 4$ </tex-math></inline-formula> dual-band stacked patch antenna array on a low-cost printed circuit board (PCB) and grouped together using two different Wilkinson networks to form two separate beamforming systems. The dual-band array demonstrates a measured effective isotropic radiated power (EIRP) of 40–42 dBm at the 28- and 39-GHz bands. The array is capable of scanning ±55° in the 28-GHz band and ±40° in the 39-GHz band, both in the azimuth plane. In simultaneous dual-frequency dual-beam operation with the 28-GHz band on the V-pol. and the 39-GHz band on the H-pol., spectrum measurement shows that the array has no visible intermodulation products between the 28- and 39-GHz beams. Also, complex modulation measurements with 64-QAM waveforms show < 3% error vector magnitude (EVM) at an EIRP of up to 36-dBm EIRP for both beams radiating together and without interference with each other. This work demonstrates the first millimeter-wave (mm-wave) 5G dual-band array and paves the way toward multistandard systems.

Nonlinear and Load-Pulling Effects in an Octave-Bandwidth Transmit Array

This article presents the design and nonlinear analysis of an octave-bandwidth transmit in-phase power combiner feed network. The goal is to evaluate the effect of nonlinearities on the in-phase spatial power combiner figures of merit (FoMs), namely effective isotropically radiated power (EIRP), overall efficiency, and linearity across a wide bandwidth and as a function of active antenna impedance and power amplifier (PA) supply voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\textrm {DD}}$ </tex-math></inline-formula> ). The analysis is showcased on a 6–12 GHz four-element array implemented with electrically small flared horns fed with microstrip-to ridge waveguide transitions, 2-W commercial gallium nitride (GaN) monolithic microwave integrated circuit (MMIC) amplifiers, and an in-phase Wilkinson power splitter. Over-the-air (OTA) measurements show an EIRP of 50 dBm over the octave bandwidth. Adjacent channel power ratio (ACPR) variation over frequency, power, and supply voltage is also measured through OTA and shows a variation of 10 dB over the considered variables.

A Zeroth-Order Slot-Loaded Cap-Shaped Patch Antenna With Omnidirectional Radiation Characteristic for UHF RFID Tag Design

The zeroth-order resonance of a compact patch structure is explored for designing a metal-mountable tag antenna in the United States (US) ultrahigh-frequency (UHF) radio frequency identification (RFID) passband. This zeroth-order resonator (ZOR) structure comprises a cap-shaped patch loaded with two L-shaped slots. Also, the patch is coupled to the ground through two inductive stubs which provide enough parasitic reactance to support the zeroth-order resonance. The proposed single-element ZOR can generate sufficient antenna impedance for achieving a conjugate match with the RFID chip impedance. Good omnidirectional radiation characteristic with vertically polarized fields can be attained in the azimuth plane when the tag antenna is placed on a metallic surface. The proposed tag antenna’s realized gain at 915 MHz is −1.382 dB [effective isotropic radiated power (EIRP) 4 W]. A stable read distance of ~15 m is obtainable with even spatial coverage in the entire azimuth plane. The resonance frequency of the proposed tag does not vary much with the object being tagged.