mmWave Bands Research Articles

Absorption‐Dominant Electromagnetic Interference (EMI) Shielding across Multiple mmWave Bands Using Conductive Patterned Magnetic Composite and Double‐Walled Carbon Nanotube Film

AbstractThe revolution of millimeter‐wave (mmWave) technologies is prompting a need for absorption‐dominant EMI shielding materials. While conventional shielding materials struggle in the mmWave spectrum due to their reflective nature, this study introduces a novel EMI shielding film with ultralow reflection (<0.05 dB or 1.5%), ultrahigh absorption (>70 dB or 98.5%), and superior shielding (>70 dB or 99.99999%) across triple mmWave frequency bands with a thickness of 400 µm. By integrating a magnetic composite layer (MCL), a conductive patterned grid (CPG), and a double‐walled carbon nanotube film (DWCNTF), specific resonant frequencies of electromagnetic waves are transmitted into the film with minimized reflection, and trapped and dissipated between the CPG and the DWCNTF. The design factors for resonant frequencies, such as the CPG geometry and the MCL refractive index, are systematically investigated based on electromagnetic wave propagation theories. This innovative approach presents a promising solution for effective mmWave EMI shielding materials, with implications for mobile communication, radar systems, and wireless gigabit communication.

Indoor Mobile Network Planning by Utilizing B5G/6G mmWave and Sub-THz Bands

Indoor Mobile Network Planning by Utilizing B5G/6G mmWave and Sub-THz Bands

A High-Gain Metallic-via-Loaded Antipodal Vivaldi Antenna for Millimeter-Wave Application

This paper presents a miniaturized-structure high-gain antipodal Vivaldi antenna (AVA) operating in the millimeter-wave (mm-wave) band. A gradient-length microstrip-patch-based director is utilized on the flares of the AVA to enhance gain. Additionally, an array of metallic vias is incorporated along the lateral and horizontal edges of the antenna for further gain enhancement and bandwidth extension. Based on the proposed structure, the AVA can achieve a peak gain of 11.9 dBi over a relative bandwidth of 71.24% within 16.5–36.6 GHz as measured, while the electrical dimension is only 1.54 × 2.69 × 0.07 λc3. The measured results show good agreement with the simulated ones. Owning the characteristics of being high-gain and ultra-wideband, and having a compact size, the proposed AVA can be a competitive candidate for future millimeter-wave communication.

Enhancing data rate and energy efficiency of NOMA systems using reconfigurable intelligent surfaces for millimeter-wave communications

In this article, we employ reconfigurable intelligent surface (RIS) to aid a non-orthogonal multiple access (NOMA) system utilizing millimeter-wave (mmWave) communications. Different to recent works on the RIS-supported NOMA systems where the certain carrier frequency was often normalized (fc=1 Hz), we analyze specific impacts of high carrier frequencies in the mmWave band (fc≥30 GHz) on the performance of the RIS-supported NOMA system. In particular, we derive the exact expressions of achievable data rate (ADR) and energy efficiency (EE) of the RIS-supported NOMA system using mmWave band (RIS-mmWave-NOMA system). We compare the ADR and EE of the RIS-mmWave-NOMA system with those of mmWave-NOMA system without RIS, where there are only source-user channels. Numerical illustrations clarify the benefits of utilizing RIS as well as the great impacts of high fc in mmWave band on the ADR and EE of the RIS-mmWave-NOMA system. More specifically, when fc increases from 50 to 100 GHz, the transmit power of source should be increased 8 dBm to achieve the same ADR. Meanwhile, the maximal EE with fc=100 GHz is greatly lower than the maximal EE with fc=50 GHz even though higher transmit power is used. In other words, when fc increases, higher transmit power can be used for the ADR aims but this method cannot be used for EE purposes. In these circumstances, utilizing a larger number of reflecting elements (REs) in the RIS is a good method. By using N≥200 REs, the ADR and EE of the RIS-mmWave-NOMA system are significantly higher than those of mmWave-NOMA system without RIS. Finally, we confirm the exactness of the derived formulas through Monte-Carlo simulations.

Highly integrable planar-structured printed circularly polarized antenna for emerging wideband internet of things applications in the millimeter-wave band

This paper proposes a numerically and experimentally validated printed wideband antenna with a planar geometry for Internet of Things (IoT) applications. This design tackles the challenges associated with deploying IoT sensors in remote areas or across extensive geographical regions. The proposed design exploits a coplanar-waveguide-fed modified microstrip line monopole for excitation of circularly polarized waves radiating in the broadside direction. The primary design is based on perturbations of the microstrip line protracted from a grounded coplanar waveguide. The capacitively coupled short rectangular stubs are periodically inserted alternately and excited asymmetrically on each side of the microstrip line parallel to the direction of the electric field vector. The sequential phase excitation of the periodic stubs generates a rectangular-cascaded electric field, which suppresses the stop band at the open end. As a result, the antenna radiates in the broadside direction. The impedance bandwidth of the antenna exceeds 8 GHz in the 28 GHz mm-wave band, i.e., it ranged from 25 to 33.5 GHz. Additionally, an axial ratio below 3 dB is achieved within the operating band from 26 to 33.5 GHz with the alterations of the surface current using straightforward topological adjustments of the physical parameters. The average in-band realized gain of the antenna is 10 dBic when measured in the broadside direction. These results indicate that the proposed design has the potential to improve the connectivity between IoT devices and the constantly varying orientation of satellites by mitigating the polarization mismatch.

Compact quad element dual band high gain MIMO rectangular dielectric resonators antenna for 5G millimeter wave application

In this article, a compact dual-band quad-port Multiple Input Multiple Output (MIMO) Rectangular Dielectric Resonator Antenna (RDRA) with a defected connected ground Geometry (DCGG) for 5G millimeter-wave (mm-wave) application is presented. The antenna is operating at 24 GHz to 32 GHz frequency range. The antenna configuration comprises four identical rectangular microstrip radiators mounted on an RT Duroid 5880 substrate (20 × 20 × 0.254) mm3. To enhance bandwidth, each radiator is equipped with both rectangular and circular-shaped ring slots. To improve the performance of the 4 port MIMO antenna, RDRAs are placed over each radiator and optimized. The MIMO RDRs exhibit dual-band with 4.24 GHz and 0.46 GHz bandwidths. The MIMO RDRA achieves exceptional isolation (>27 dB), high gain (8.24 dB), and more than 94 % radiation efficiency. The diversity parameters exhibit a low Envelope Correlation Coefficient (ECC) of 0.0006, and a high Diversity Gain (DG) of 9.97 dB is achieved, highlighting the effectiveness of the antenna system in providing diversity reception and improving communication reliability in challenging environments. Hence, the proposed MIMO antenna is compact, making it suitable for integration into small 5G devices or systems where space is limited, such as IoT devices, mobile phones, or small base stations at mm-wave frequency bands.

A Broadband Millimeter-Wave 5G Low Noise Amplifier Design in 22 nm Fully Depleted Silicon-on-Insulator (FD-SOI) CMOS

This paper presents a broadband millimeter-wave (mm-Wave) low noise amplifier (LNA) designed in a 22 nm fully depleted silicon-on-insulator (FD-SOI) CMOS technology. Electromagnetic (EM) simulations suggest that the LNA has a 3-dB bandwidth (BW) from 17.8 to 42.4 GHz and a fractional bandwidth (FBW) of 81.7%, covering the key frequency bands within the mm-Wave 5G FR2 band, with its noise figure (NF) ranging from 2.9 to 4.9 dB, and its input-referred 1-dB compression point (IP1dB) of −17.9 dBm and input-referred third-order intercept point (IIP3) of −8.5 dBm at 28 GHz with 15.8 mW DC power consumption (PDC). Using the FOM (figure-of-merit) developed for broadband LNAs (FOM = 20 × log((Gain[V/V] × S21-3 dB-BW [GHz])/(PDC [mW] × (F-1)))), this LNA achieves a competitive FOM (FOM = 18.9) among reported state-of-the-art mm-Wave LNAs in the literature.

Low mutual coupling miniaturized dual-band quad-port MIMO antenna array using decoupling structure for 5G smartphones

Maintaining the compactness of 5G smartphones while accommodating millimeter-wave (mm-wave) bands presents a significant challenge due to the substantial difference in frequency. To tackle this issue, we introduce a miniaturized quad-port dual-band multiple-input, multiple-output (MIMO) antenna with low mutual coupling (MC) and a considerable frequency difference. This quad-port MIMO antenna, built on a Rogers TMM4 substrate, measures 17.76 × 17.76 mm2 and boasts a dielectric constant of 4.5. It incorporates four planar patch antennas, positioned at the corners in perpendicular orientations. For dual-band operation at 28/38 GHz, each antenna element features a rectangular patch with four rectangular slots, complemented by a full ground plane. The spacing between these elements is 0.5 λo, and we've included a decoupling structure (DS) to minimize mutual coupling (MC) among the MIMO antenna elements with minimal complexity and cost. Simulation and measurement results reveal a significant reduction in mutual coupling between the array elements, ranging from − 25 to − 60 dB. As a result, we’ve developed the envelope correlation coefficient (ECC) and made advancements in the total active reflection coefficient (TARC), mean effective gain (MEG), and diversity gain (DG). The measured gains for this design are approximately 8.9 dBi at both 28 GHz and 38 GHz, with a radiation efficiency of nearly 93%. Furthermore, specific absorption rate (SAR) analysis confirms the MIMO antenna's suitability for smartphone handsets operating within the target frequency band.

Design of novel microstrip patch antenna for millimeter-wave B5G communications

Introduction: The simplicity of integration and co-type features of microstrip antennas make them intriguing for a broad variety of applications, particularly with the growing usage of mmWave bands in wireless communications and the constant rise in data transfer in communication situations.Method: This paper proposes a novel design of micrstrip patch antenna for mmWave B5G communication. The main idea is to realize four-mode antenna the operates in four different frequencies. The geometry is rectangular patch whose resonance frequency is adjusted by varying the walls and pins of the structure.Results: Simulation results show that the proposed antenna design has improved fractional bandwidth and performance as compared with existing antennas.Discussion: The observed curve indicates that, in agreement with the modeling findings, there are four resonance spots in the operational frequency region of 2.5–3.4 GHz: 2.68 GHz, 2.9 GHz, 3.05 GHz, and 3.3 GHz, which correspond to TM1/2,0, TM3/2,0, and TMRS, respectively, and TM1/2,2 four resonant modes, within the frequency range, the observed antenna gain peak is around 9 dBi, which is consistent with the measured results.

CRLH Leaky-Wave Antenna with High Gain and Wide Beam-Scanning Angle for 5G mmWave Applications

In this paper, a novel composite right-/left-handed (CRLH) leaky-wave antenna with a simple structure, low cost, high gain, and wide beam-scanning range performance for the millimeter wave (mmWave) band. The proposed antenna comprises a series-fed array of asymmetrically slotted elliptical CRLH unit cells loaded with a short-circuit stub. By optimizing the length of the stub, the condition of the CRLH structure is balanced to enable beam scanning from the backward to the forward direction within the mmWave band. The proposed antenna exhibits a wide beam-scanning angle of 112° (-60° to 52°), coupled with high gain and radiation efficiency at the designated band. Furthermore, it is fabricated on a traditional microwave substrate, Rogers RT/duroid 5880, thus offering a cost-effective approach to streamlining the manufacturing process. The measurement results confirmed a peak realized gain of 16.8 dBi. The excellent performance achieved using a low-cost design makes the proposed antenna attractive for 5G mmWave applications.

A 26-28 GHz, Two-Stage, Low-Noise Amplifier for Fifth-Generation Radio Frequency and Millimeter-Wave Applications.

This paper presents a high-gain low-noise amplifier (LNA) operating at the 5G mm-wave band. The full design combines two conventional cascode stages: common base (CB) and common emitter (CS). The design technique reduces the miller effect and uses low-voltage supply and low-current-density transistors to simultaneously achieve high gain and low noise figures (NFs). The two-stage LNA topology is analyzed and designed using 0.25 µm SiGe BiCMOS process technology from NXP semiconductors. The measured circuit shows a small signal gain at 26 GHz of 26 dB with a gain error below 1 dB on the entire frequency band (26-28 GHz). The measured average NF is 3.84 dB, demonstrated over the full frequency band under 15 mA current consumption per stage, supplied with a voltage of 3.3 V.

Centre Extended Rectangular Microstrip Patch Antenna for Satellite Applications

The advancement of wireless communication systems has resulted in the evolution of fifth-generation (5G) communication systems, which utilize mm-wave bands to achieve high data rates. 5G communication systems require antennas with high gain, low profile, lightweight, and very simple structures to ensure reliability, ease of fabrication, low cost, and high efficiency. This paper proposes the design of a single-element rectangular microstrip patch antenna that operates in the C-band at 7.1 GHz and the X-band at 9.2 GHz. The proposed antenna is simulated using Advanced Design System (ADS) software. To meet the requirements of the proposed antenna, such as high efficiency and gain, the patch is slightly modified with a mm extension of length at the center, and the performance of the antenna is studied in terms of antenna parameters such as return loss, VSWR, gain, and radiation pattern.

Dual-band frequency reconfigurable metasurface antenna for millimeter wave joint communication and radar sensing systems

This paper introduces an innovative, compact, and high-gain metasurface antenna, covering both the 24 GHz millimeter wave (mmWave) radar band and the 5 G n257 and n258 bands. The proposed metasurface antenna consists of a wideband stacked patch antenna and a dual-layer metasurface to focus its radiation beams for multiple mmWave bands. The operating frequency can be slightly shifted by altering the distance between the feeder and the metasurface. The distribution of the metasurface unit cells is designed based on a simplified phase compensation formula. The dimension of the fabricated feeder is 6 mm × 6 mm, and the metasurface occupies a 65 mm × 65 mm radome area. Experimental results demonstrate a wide bandwidth from 23.5 GHz to 29.1 GHz for the feeder, and impressive maximum gains of 19.7 dBi and 19.5 dBi for the lower band and higher band of the metasurface antenna are achieved simultaneously. The frequency reconfiguration ability was characterized by a 750 MHz frequency shift with every 1 mm distance adjustment. The compact size and high gain performance of the proposed design underscore its potential for practical applications in millimeter wave joint communication and radar sensing systems.

Network-assisted full-duplex cell-free mmWave networks: Hybrid MIMO processing and multi-agent DRL-based power allocation

This paper investigates the network-assisted full-duplex (NAFD) cell-free millimeter-wave (mmWave) networks, where the distribution of the transmitting access points (T-APs) and receiving access points (R-APs) across distinct geographical locations mitigates cross-link interference, facilitating the attainment of a truly flexible duplex mode. To curtail deployment expenses and power consumption for mmWave band operations, each AP incorporates a hybrid digital–analog structure encompassing precoder/combiner functions. However, this incorporation introduces processing intricacies within channel estimation and precoding/combining design. In this paper, we first present a hybrid multiple-input multiple-output (MIMO) processing framework and derive explicit expressions for both uplink and downlink achievable rates. Then we formulate a power allocation problem to maximize the weighted bidirectional sum rates. To tackle this non-convex problem, we develop a collaborative multi-agent deep reinforcement learning (MADRL) algorithm called multi-agent twin delayed deep deterministic policy gradient (MATD3) for NAFD cell-free mmWave networks. Specifically, given the tightly coupled nature of both uplink and downlink power coefficients in NAFD cell-free mmWave networks, the MATD3 algorithm resolves such coupled conflicts through an interactive learning process between agents and the environment. Finally, the simulation results validate the effectiveness of the proposed channel estimation methods within our hybrid MIMO processing paradigm, and demonstrate that our MATD3 algorithm outperforms both multi-agent deep deterministic policy gradient (MADDPG) and conventional power allocation strategies.

Phase Noise Compensation Techniques for Arbitrary Reference Signal Configurations in mmWave and Sub-THz Bands

Phase Noise Compensation Techniques for Arbitrary Reference Signal Configurations in mmWave and Sub-THz Bands

Effects of Superstrate layer on the Performance of 5G Microstrip Antenna Operating at 43.5GHz

The fifth generation (5G) technology working at mm-wave bands is introduced to achieve high data and large capacity, but mm-waves suffer from space attenuation. 5G systems requires antennas with simple configuration, light weight, and high gain to overcome free space attenuations.This paper aims to design 5G microstrip antenna operating at of 43.5 GHz within the frequency band of 42-45 GHz. The proposed antenna is designed on FR4 substrate with dielectric constant of 4.4 and thickness of 0.76mm, and simulated using High Frequency Structure Simulator (HFSS) software. To evaluate the performance of this antenna, the characteristics such as radiation pattern and gain are studied. Moreover, the influence of superstrate on the antenna performance is investigated based on changing dialectic constant and thickness of superstrate.

A Wideband Non-Stationary 3D GBSM for HAP-MIMO Communication Systems at Millimeter-Wave Bands

High-altitude platforms (HAPs) are considered to be the most important equipment for next-generation wireless communication technologies. In this paper, we investigate the channel characteristics under the configurations of massive multiple-input multiple-output (MIMO) space and large bandwidth at millimeter-wave (mmWave) bands, along with the moving essence of the HAP and ground terminals. A non-stationary three-dimensional (3D) geometry-based stochastic model (GBSM) is proposed for a HAP communication system. We use a cylinder-based geometric modeling method to construct the channel and derive the channel impulse response (CIR). Additionally, the birth–death process of the scatterers is enclosed using the Markov process. Large-scale parameters such as free space loss and rainfall attenuation are also taken into consideration. Due to the relative motion between HAP and ground terminals, the massive MIMO space, and the wide bandwidth in the mmWave band, the channel characteristics of HAP exhibit non-stationarities in time, space, and frequency domains. By deriving the temporal auto-correlation function (ACF), we explore the non-stationarity in the time domain and the impact of various parameters on the correlations across the HAP-MIMO channels. The spatial cross-correlation function (CCF) for massive MIMO scenarios, and the frequency correlation function (FCF) in the mmWave bands are also considered. Moreover, we conduct simulation research using MATLAB. Simulation results show that the theoretical results align well with the simulation results, and this highlights the fact that the constructed 3D GBSM can characterize the non-stationary characteristics of HAP-MIMO channels across the time, space, and frequency domains.

Real-time millimeter wave holography with an arrayed detector.

Millimeter and terahertz wave imaging has emerged as a powerful tool for applications such as security screening, biomedical imaging, and material analysis. However, intensity images alone are often insufficient for detecting variations in the dielectric constant of a sample, and extraction of material properties without additional phase information requires extensive prior knowledge of the sample. Digital holography provides a means for intensity-only detectors to reconstruct both amplitude and phase images. Here we utilize a commercially available source and detector array, both operating at room temperature, to perform digital holography in real-time for the first time in the mm-wave band (at 290 GHz). We compare the off-axis and phase-shifting approaches to digital holography and discuss their trade-offs and practical challenges in this regime. Owing to the low pixel count, we find phase-shifting holography to be the most practical and high fidelity approach for such commercial mm-wave cameras even under real-time operational requirements.

Dual-Band Coradiator Antenna Employing Cascaded Triangular Cavities With a Steerable Beam in the Millimeter-Wave Band

A dual-band coradiator antenna with a beam-scanning capability for the sub-6 GHz andmm-wave bands is proposed in this paper. First, four subarrays based on cascaded triangular cavities are arranged using a mirror operation to form the mm-wave antenna array. Then, four mm-wave subarrays are connected at the position where the electric field is at a minimum on their edges. Lastly, the entire mm-wave array structure resonates in the microwave band, which can be equivalent to a shorted quarter-wavelength patch antenna in the sub-6 GHz band. Hence, the same radiator can work as both a sub-6 GHz antenna and a mm-wave antenna array with broadside patterns in both cases. Attributed to the novel co-radiator structure, the proposed design is simple and compact. An interdigital coupled line with a high-pass filtering characteristic is inserted into each mm-wave feeding line to enhance the isolation. Besides, two parasitic patches are loaded to increase the microwave bandwidth. The experimental results show that the peak gain at 2.56 GHz is 3.2 dBi and at 28 GHz is 14.3 dBi for the sub-6 GHz and mm-wave bands, respectively. The isolation among different feeding ports is greater than 15 dB and the mm-wave array also provides ±38° beam scanning performance.

System-Level Assessment of Massive Multiple-Input–Multiple-Output and Reconfigurable Intelligent Surfaces in Centralized Radio Access Network and IoT Scenarios in Sub-6 GHz, mm-Wave, and THz Bands

System-Level Assessment of Massive Multiple-Input–Multiple-Output and Reconfigurable Intelligent Surfaces in Centralized Radio Access Network and IoT Scenarios in Sub-6 GHz, mm-Wave, and THz Bands