mmWave Bands Research Articles

Novel directive antenna based on parabolic quasi Fabry–Pérot cavity

Parabolic reflectors have very good directivity. However, when put behind a partially reflecting surface, they suffer from destructing in-phase rays and they experience deteriorated characteristics. In this work we consider fixing this impediment and we enhance the low profile by providing a new approach based on ray optics model. This approach grabs the equations of multiple reflections between the two components to re-construct a collimated beam in the normal direction of the radiated element. This model is confirmed with a peak simulated directivity of about 28 dB of the new compact parabolic quasi Fabry–Pérot cavity. The highly directive and low profile proposed model is valid for both microwave and mmWave bands (from 5 to 60 GHz). The measured realized gain of the fabricated prototype is compared with a simulated data resulting in a peak of about 25.2 dB.

The Uses of a Dual-Band Corrugated Circularly Polarized Horn Antenna for 5G Systems.

This paper presents the development of a wide-beam width, dual-band, omnidirectional antenna for the mm-wave band used in 5G communication systems for indoor coverage. The 5G indoor environment includes features of wide space and short range. Additionally, it needs to function well under a variety of circumstances in order to carry out its diverse set of network applications. The waveguide antenna has been designed to be small enough to meet the requirements of mm-wave band and utilizes a corrugated horn to produce a wide beam width. Additionally, it is small enough to integrate with 5G communication products and is easy to manufacture. This design is simple enough to have multi-feature antenna performance and is more useful for the femtocell repeater. The corrugated circularly polarized horn antenna has been designed for two frequency bands; namely, 26.5–30 GHz for the low band and 36–40 GHz for high band. The results of this study show that return-loss is better than 18 dB for both low and high band. The peak gain is 6.1 dBi for the low band and 8.7 dBi for the high band. The beam width is 105 degrees and 77 degrees for the low band and the high band, respectively. The axial ratio is less than 5.2 dB for both low and high band. Generally, traditional circularly polarized antennas cannot meet the requirements for broadband. The designs for the antennas proposed here can meet the requirements of FR2 bandwidths. This feature limits axial ratio performance. The measurement error in the current experiment comes from the high precision control on the size of the ridge.

Decentralized joint resource allocation and path selection in multi-hop integrated access backhaul 5G networks

Cell densification has recently been considered as a solution to the high bandwidth demand from the ever-increasing number of connected devices as well as the emerging bandwidth-thirsty applications in 5 G networks. Ultra-dense networks suffer from backhaul bottlenecks. Wireless backhaul connections, especially in the mm-wave bands, have become attractive solutions for the backhaul bottleneck problem. The third-generation partnership project (3GPP) introduced a new Integrated Access Backhaul (IAB) study item in which the same spectral resources are dynamically used for both access and backhaul connections. In densified multi-hop topologies, especially when more than one fiber-linked node exists, it is difficult to solve the problem of resource allocation in a centralized manner. Trying to address this, we propose a distributed stochastic scheme to jointly solve the problem of resource/bandwidth allocation and path selection in a multi-hop multi-path IAB mm-wave 5 G network. First, a Directed Acyclic Graph (DAG) topology formation algorithm is proposed. This algorithm does cell search and performs initial access procedures. It spreads information across child/parent links about the topology. Then, stochastic optimization tools are employed for path selection from the resource perspective. We study the efficiency of the proposed scheme in exploiting resources. Additionally, we explore the effects of stochastic information spread in the topology and also the probability levels on the performance of our scheme. Our analyses show that the proposed distributed scheme yields nearly the same performance as an optimal centralized algorithm in joint resource allocation and path selection tasks. This alternative can take the place of centralized resource management, especially in scenarios where central resource allocation is not possible. In comparison, our scheme outperforms traditional load-based resource partitioning algorithms in the allocation of resources by up to 20%. Results also show that our scheme exploits the resources similar to what an instantaneous load-based strategy does, but without the need for excessive signalings.

Substrate integrated coaxial line design for mmWave antenna with multilayer configuration

In the 5G communication utilizing millimeter-wave (mmWave) band, multilayer configuration is popular for mmWave antenna with module-level integration and high-density design. However, multilayer construction adds several substrate layers and metallic ground layers to RF signal paths, which induces extra capacitances and inductances to the original antenna, thereby deteriorating impedance matching, and distorting radiation patterns. In this paper, we investigate the influence of multilayer structure on antenna performances, and apply substrate integrated coaxial line (SICL) design to eliminate these interferences from multilayer configuration. Equivalent circuit model of the multilayer configuration with SICL is presented and verified by simulations. A mmWave antenna unit and the 1 × 4 array in multilayer configuration with SICL design are measured. Experiments show that SICL design enables impedance matching and radiation patterns to be maintained without distortions when applying multiple layers to the mmWave antenna, validating this method. It can be applied to 5G mmWave antennas that desire multilayer construction.

A Millimeter-Wave Tri-Modal Patch Antenna

This letter presents a millimeter-wave (mmWave) tri-modal patch antenna with a size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.46\,\lambda _{0}\times 0.46\,\lambda _{0}\times 0.11\,\lambda _{0}$</tex-math></inline-formula> , in which <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula> is the wavelength in air at the center frequency. It is the first example of a tri-modal patch antenna in the mmWave frequency range. Compared to previous sub-6 GHz tri-modal patches, special approaches to handle the three port excitation at mmWave are required. The radiation performance with various feeding structures, fabrication approaches, and the challenges of designing tri-modal patch antennas in mmWave bands are detailed. The advantage of utilizing the tri-modal patch concept is that with proper excitation, a compact three-port antenna can be designed to exhibit broadside radiation and low mutual coupling within a single element. Experimental results demonstrate a three-port antenna operating at 26 GHz with an impedance bandwidth and realized gain of 5.4% and 5.0 dBi, respectively, which is suitable for use as a unit cell in mmWave massive multiple-input--multiple-output (MIMO) antenna applications.

Performance Analysis of Inter-Cell Interference Coordination in mm-Wave Cellular Networks

In millimeter-wave (mm-wave) cellular networks, directional antenna arrays are typically adopted to mitigate the severe propagation loss. However, the interference caused by such highly directional beams may, in turn, result in a significant number of transmission failures, especially for dense networks. To tackle this problem, we propose two inter-cell interference coordination (ICIC) schemes in mm-wave bands: one is merely based on the path loss incorporating the blockage effect (PL-ICIC); the other considers both path loss and directivity gain (PG-ICIC). To fully investigate both schemes, we first derive an exact expression for the success probability (reliability) of the typical (served) user. We further provide an asymptotic analysis for the success probability and propose an effective approximation based on the asymptotic signal-to-interference ratio (SIR) gain relative to no ICIC. Secondly, to incorporate the cost of ICIC schemes, we derive the approximate normalized throughput taking into account that some users cannot be served due to limited resources. Numerical results show that the two proposed schemes provide significant reliability improvements in the low-SIR regime, and the higher the number of antennas, the wider the SIR range for which there is an improvement. In addition, compared with PL-ICIC, PG-ICIC balances the available resources among all users well.

Performance of Remote Radio Unit Selection in Millimeter-Wave Distributed Antenna Systems Over Fluctuating Two-Ray Fading

Millimeter wave (mmWave) is a promising future wireless communication technology. To overcome the high path loss in mmWave band, distributed antenna systems (DASs) with each base station (BS) connecting to multiple remote radio units (RRUs) is a candidate solution. To better characterize the small-scale fading of mmWave channels, the fluctuating two-ray (FTR) was recently proposed. In this letter, we study the performance of RRU selection in mmWave DASs over the FTR fading. First, simplified closed-form expressions are, respectively, provided for the probability density function (PDF) and cumulative distribution function (CDF) of signal-to-noise ratio (SNR). Then, we derive the exact closed-form expressions and their high-SNR approximations for the outage probability and ergodic rate, respectively. The effect of RRU number and FTR-fading parameters on the performance are further revealed from these high-SNR approximations. Simulations validate our analytical results.

Resource Management for 5G NR Integrated Access and Backhaul: A Semi-Centralized Approach

The next generations of mobile networks will be deployed as ultra-dense networks, to match the demand for increased capacity and the challenges that communications in the higher portion of the spectrum (i.e., the mmWave band) introduce. Ultra-dense networks, however, require pervasive, high-capacity backhaul solutions, and deploying fiber optic to all base stations is generally considered to be too expensive for network operators. The 3rd Generation Partnership Project (3GPP) has thus introduced Integrated Access and Backhaul (IAB), a wireless backhaul solution in which the access and backhaul links share the same hardware, protocol stack, and also spectrum. The multiplexing of different links in the same frequency bands, however, introduces interference and capacity sharing issues, thus calling for the introduction of advanced scheduling and coordination schemes. This paper proposes a semi-centralized resource allocation scheme for IAB networks, designed to be flexible, with low complexity, and compliant with the 3GPP IAB specifications. We develop a version of the Maximum Weighted Matching (MWM) problem that can be applied on a spanning tree that represents the IAB network and whose complexity is linear in the number of IAB-nodes. The proposed solution is compared with state-of-the-art distributed approaches through end-to-end, full-stack system-level simulations with a 3GPP-compliant channel model, protocol stack, and a diverse set of user applications. The results show that our scheme can increase the throughput of cell-edge users up to 3 times, while decreasing the overall network congestion with an end-to-end delay reduction of up to 25 times.

Uplink Performance of MmWave-Fronthaul Cell-Free Massive MIMO Systems

Cell-free (CF) massive multiple-input multiple-output (mMIMO) is a promising candidate to support the requirements of the fifth-generation (5 G) and beyond networks. However, the capacity of the fronthaul network dramatically influences its performance. While wired fronthaul links can be seen as the optimal choice, they may not be practically feasible. Exploiting the enormous bandwidth available in the millimeter-Wave (mmWave) band to support the fronthaul links paves the way to achieve the full potential of CF mMIMO systems. In this paper, we investigate the uplink (UL) performance of CF mMIMO systems supported by mmWave-fronthaul networks. Using tools from stochastic geometry, we derive analytical expressions for both the distribution of the provided fronthaul capacity and the average UL data rates. We show that although increasing the density of blockages degrades the average UL data rates, increasing the density of CPUs can limit such effect. Moreover, the obtained results reveal that the network deployment should be adjusted according to the available fronthaul bandwidth and the density of blockages. In particular, for a given fronthaul bandwidth, increasing the density of APs beyond a certain limit would not achieve further improvement in the UL data rates. Besides, increasing the number of antennas per AP may even cause a degradation in the system performance.

Double Intelligent Reflecting Surface-Assisted Multi-User MIMO Mmwave Systems With Hybrid Precoding

This work investigates the effect of double intelligent reflecting surface (IRS) in improving the spectrum efficient of multi-user multiple-input multiple-output (MIMO) network operating in the millimeter wave (mmWave) band. Specifically, we aim to solve a weighted sum rate maximization problem by jointly optimizing the digital precoding at the transmitter and the analog phase shifters at the IRS, subject to the minimum achievable rate constraint. To facilitate the design of an efficient solution, we first reformulate the original problem into a tractable one by exploiting the majorization-minimization (MM) method. Then, a block coordinate descent (BCD) method is proposed to obtain a suboptimal solution, where the precoding matrices and the phase shifters are alternately optimized. Specifically, the digital precoding matrix design problem is solved by the quadratically constrained quadratic programming (QCQP), while the analog phase shift optimization is solved by the Riemannian manifold optimization (RMO). The convergence and computational complexity are analyzed. Finally, simulation results are provided to verify the performance of the proposed design, as well as the effectiveness of double-IRS in improving the spectral efficiency.

A 37-GHz Asymmetric Doherty Power Amplifier With 28-dBm P sat and 32% Back-Off PAE in 0.1-μm GaAs Process

In this article, the analysis, design, and development of a 37-GHz asymmetric Doherty power amplifier (DPA) are presented. In a practical DPA, the main power amplifier (PA) shows nonideal characteristic, which varies the effect of the load modulation. Based on the theoretical analysis, we derive the relationship among the efficiency, power back-off (PBO) level, and the corresponding load impedance in a nonideal load modulation. The result suggests that a Class-AB main PA shows a decreased PBO efficiency during the load modulation. To achieve a good compromise between PBO level and PBO efficiency of the main PA, the load modulation scheme is redesigned in this work. A 2-dB PBO of the main PA is chosen to maintain the high efficiency during the load modulation. An asymmetric DPA topology is employed to compensate the inadequate PBO of the main PA so that a desired 6-dB PBO is achieved. Generally, the RF leakage at the DPA output degrades its performance. To solve this issue, we propose a modified low characteristic impedance DPA output network. The output matching network of the auxiliary PA is particularly designed to enlarge its output impedance. Through these design techniques, the leakage loss is significantly reduced to 0.2 dB, which improves the gain and power-added efficiency (PAE) at PBO. To validate the proposed techniques, a DPA chip is designed and fabricated in a D-mode 0.1- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> GaAs pHEMT process. At 37 GHz, the 1.6 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times1.8$ </tex-math></inline-formula> mm integrated chip exhibits a measured small-signal gain of 15.6 dB and a saturated power ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm{sat}}$ </tex-math></inline-formula> ) of 28.0 dBm, with an associated 33.2% peak PAE and a 32.0% PAE at 6-dB PBO. To the best of our knowledge, the proposed chip exhibits the state-of-the-art overall performance among DPAs operating around 37 GHz for 5G n260 millimeter-wave (mm-wave) band.

A miniaturised Ka/V dual band millimeter wave antenna for 5G body centric network applications

Body centric Networks (BCNs) are the most important and attractive part of the next generation (5G and beyond) wireless technologies having a plethora of applications in day to day life. However the design of antennas for BCNs is a challenging task. Such antennas should have small size, light weight, higher gain and larger bandwidth besides having a stable radiation pattern under the influence of human body effects. This paper presents a miniaturised Ka/V dual band mmWave microstrip antenna for 5G BCN applications. The antenna has very small dimensions of 2.28 × 3.06 × 0.14 mm3 and operates at 33.5 GHz (Ka band) and 60.8 GHz (V band). The performance of the antenna is examined for “Off-body, On-body and In-body” BCN application scenarios. The radiation pattern, return loss, peak gain and −10 dB bandwidth results reveal that the antenna performs quite well at all interested frequencies. A comparative study with state of art mmWave antennas also shows the effectiveness of the proposed antenna.

Adaptive beamwidth optimization under Doppler ICI and positioning errors at mmWave bands

The growing trends towards massive antenna arrays with focusing capabilities has enabled the use of higher frequencies at the cost of more complex systems. In the particular case of vehicular communications, millimeter-wave (mmWave) communications are expected to unleash a set of advanced use cases with stringent spectrum needs. However, dealing with very directive patterns and high frequencies entail additional challenges such as beam misalignment and Doppler effect. This paper presents a beam optimization procedure for vehicle-to-network (V2N) systems in which a base station communicates with high-speed users. Aided by the a priori knowledge of the vehicle location, the base station is able to estimate the average signal-to-interference-plus-noise ratio (SINR) until the next beam refresh considering the positioning accuracy and the Doppler inter-carrier interference (ICI). The estimation includes the antenna beamwidth, which can be optimized to maximize the achievable throughput. The numerical results indicate that the SINR can be significantly enhanced compared to beam sweeping with identical hierarchical codebooks while reducing the probability of outage.

Hybrid Direction of Arrival Precoding for Multiple Unmanned Aerial Vehicles Aided Non-Orthogonal Multiple Access in 6G Networks

Unmanned aerial vehicles (UAV) have attracted increasing attention in acting as a relay for effectively improving the coverage and data rate of wireless systems, and according to this vision, they will be integrated in the future sixth generation (6G) cellular network. Non-orthogonal multiple access (NOMA) and mmWave band are planned to support ubiquitous connectivity towards a massive number of users in the 6G and Internet of Things (IOT) contexts. Unfortunately, the wireless terrestrial link between the end-users and the base station (BS) can suffer severe blockage conditions. Instead, UAV relaying can establish a line-of-sight (LoS) connection with high probability due to its flying height. The present paper focuses on a multi-UAV network which supports an uplink (UL) NOMA cellular system. In particular, by operating in the mmWave band, hybrid beamforming architecture is adopted. The MUltiple SIgnal Classification (MUSIC) spectral estimation method is considered at the hybrid beamforming to detect the different direction of arrival (DoA) of each UAV. We newly design the sum-rate maximization problem of the UAV-aided NOMA 6G network specifically for the uplink mmWave transmission. Numerical results point out the better behavior obtained by the use of UAV relays and the MUSIC DoA estimation in the Hybrid mmWave beamforming in terms of achievable sum-rate in comparison to UL NOMA connections without the help of a UAV network.

5G/B5G Internet of Things MIMO Antenna Design

The current and future wireless communication systems, WiFi, fourth generation (4G), fifth generation (5G), Beyond5G, and sixth generation (6G), are mixtures of many frequency spectrums. Thus, multi-functional common or shared aperture antenna modules, which operate at multiband frequency spectrums, are very desirable. This paper presents a multiple-input and multiple-output (MIMO) antenna design for the 5G/B5G Internet of Things (IoT). The proposed MIMO antenna is designed to operate at multiple bands, i.e., at 3.5 GHz, 3.6 GHz, and 3.7 GHz microwave Sub-6 GHz and 28 GHz mm-wave bands, by employing a single radiating aperture, which is based on a tapered slot antenna. As a proof of concept, multiple tapered slots are placed on the corner of the proposed prototype. With this configuration, multiple directive beams pointing in different directions have been achieved at both bands, which in turn provide uncorrelated channels in MIMO communication. A 3.5 dBi realized gain at 3.6 GHz and an 8 dBi realized gain at 28 GHz are achieved, showing that the proposed design is a suitable candidate for multiple wireless communication standards at Sub-6 GHz and mm-wave bands. The final MIMO structure is printed using PCB technology with an overall size of 120 × 60 × 10 mm3, which matches the dimensions of a modern mobile phone.

Protocol Solutions for IEEE 802.11bd by Enhancing IEEE 802.11ad to Address Common Technical Challenges Associated With mmWave-Based V2X

A multi-gigabit (WiGig) system is designed based on IEEE 802.11ad standards by exploiting millimeter-wave (mmWave) bands to achieve extremely high data rates. IEEE 802.11bd and 3GPP NR V2X are two new specifications for the next-generation vehicle-to-everything (V2X) network with the capability to support mmWave bands. However, mmWave bands could be the solution for the high throughput and low latency. Still, the instability of blockages is a substantial challenge in mmWave bands, rendering mmWave ineffective in vehicular networks. Typically, technologies capable of operating at mmWave bands, such as IEEE 802.11ad, IEEE 802.11bd, NR- V2X, etc., share the same technical limitations due to the mmWave characteristics. Therefore, to achieve the aspirations of next generation connected mmWave V2X vehicles. In this paper, we propose classic, cooperative, and extension protocols for IEEE 802.11bd by enhancing IEEE 802.11ad. The proposed solution aims to mitigate some of the most common technical challenges associated with using mmWave bands in V2X networks, such as beam training overhead, link blockage, and limited coverage range. Simulation results demonstrate that the proposed approach effectively reduces the beam training overhead, overcomes link blockage, increases the probability of line-of-sight (LOS), and extends the coverage range. Further, the proposed enhancement achieves significantly higher performance against the conventional solution and shows more link stability despite continuous changes in vehicle density.

Ultra-Wideband Hybrid Magneto-Electric Dielectric-Resonator Dipole Antenna Fed by a Printed RGW for Millimeter-Wave Applications

Future communication standards have an increasing interest in Millimeter Wave (mm-wave) bands, where wide bandwidth and secured communication can be assured. This trend in communication standards stimulates the research community to provide novel antenna configurations in the mm-wave bands. This article proposes a novel design and analysis of hybrid magneto-electric dielectric-resonator dipole antenna that features an electrically small size with ultra-wideband operation and consistent radiation characteristics in the mm-wave band. The proposed antenna is designed based on the combination of multi-resonances produced by a Magneto-Electric (ME) dipole and stacked Dielectric Resonator Antennas (DRAs). In addition, the proposed antenna is implemented using state-of-the-art Printed Circuit Board (PCB) technology, namely, Printed Ridge Gap Waveguide (PRGW) for low loss and cost-efficiency. The combination between the ME-dipole and stacked DRA is adopted to ensure symmetric radiation characteristics in both E- and H-planes over ultra-wideband operation with a deep matching level. Both DRA and ME-dipole elements are designed and studied separately, where a systematic design procedure is presented to obtain initial design parameters. Proper integration between the radiating elements introduced an electrically small size antenna ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.64\,\,\lambda \times 0.48\lambda $ </tex-math></inline-formula> ) covers the full Ka-band (26-40 GHz) with a matching level beyond −20 dB and gain stability of 8± 1 dB. The antenna prototype is fabricated, where a good agreement is shown between both simulated and measured results.

Sub-6 GHz and mm-Wave 5G Vehicle-to-Everything (5G-V2X) MIMO Antenna Array

A multi-beam and multi-polarized Multiple-Input Multiple-Output (MIMO) antenna system, which operates at Sub-6 GHz and mm-wave frequency bands is realized for 5G Vehicle-to-Everything (5G-V2X) application. Since the vehicle needs to communicate in different scenarios with the others, e.g. vehicles, passengers, control units, and mobile networks, in the surrounding area, an antenna with 360° coverage area is required. In this paper, an eight-element MIMO antenna is designed and implemented for this purpose. Four elements are distributed evenly in a circular substrate placed in the azimuth plane. Meanwhile, the other four elements are printed on two orthogonal substrates which are fixed perpendicularly to the circular substrate. Each radiating component is a tapered slot antenna integrated with a dipole to operate at both microwave and mm-wave bands. The simulated and measured results demonstrate capability of the proposed design in covering the whole surrounding area (360° coverage in azimuth plane). The antenna achieves a realized gain of more than 9 dBi at the mm-wave range and 4 dBi at the microwave range.

Design Methodology of Multiband Printed Antennas for Future Generations of Mobile Handsets

The present paper introduces a design methodology to extend the operation of a microstrip patch antenna to operate efficiently at multiple higher-order resonances. This method depends on the geometrical modification of the antenna structure by adding well-designed inductively-loaded and capacitively-coupled elements to the primary patch so that it can efficiently radiate at the desired higher frequency bands. It is explained quantitatively how to use the geometrical parameters of the inductively and capacitively coupled elements for accurate tuning of the multiple resonant frequencies of the antenna. The proposed method is applied to modify a primary hexagonal patch antenna (designed to principally radiate at 28 GHz as its first-order resonance) so as to operate at additional higher frequency bands around 43, 52, and 57 GHz. Also, an alternative design is provided for a quad-band printed antenna of composite patch structure that operates in the same millimetric-wave (mm-wave) bands, 28, 43, 52, and 57 GHz with high radiation efficiency, excellent impedance matching, and satisfactory values of the antenna gain. The corresponding frequency bands are, respectively, (27.7-28.3 GHz), (42.7-43.3 GHz), (51.2-53.0 GHz), and (55.7-57.5 GHz). The dimensions of the area occupied by the primary patch and the parasitic elements are 5.2 &#x00D7; 3.3 mm².&#x2013; The two antennas are fabricated for experimental assessment of their performance including the impedance matching and radiation patterns. It is shown that the experimental measurements come in agreement with the simulation results over all the four operational mm-wave frequency bands. One of the advantages of the proposed method is that it can be applied to patch antennas of arbitrary shapes and is not restricted to hexagonal patch antennas. Furthermore, this method is not restricted by extending the operation of the antenna to radiate at four frequency bands. It is capable of adding any desired number of frequency bands so that the antenna can operate at five or, even, more bands.

Compact and Integrated Microstrip Antenna Modules for mm-Wave and Microwave Bands Applications

This paper presents two different antenna modules at two different bands with a compact size structure that is used for both of mm-Wave and microwave bands, with the objective of keeping the size as minimum as possible. The presented structure consists of two integrated modules with overall dimensions of 24 <inline-formula> <tex-math notation="LaTeX">$\times 15\times0.787$ </tex-math></inline-formula> mm³ and is implemented on a Rogers RT5880 substrate. The first module is designed to resonate at 25.75 GHz with bandwidth of 4.15 GHz. The length of this module is taken as a constraint in designing the second module, which is the microwave one. This module is designed to have resonance frequency of 5.45 GHz with bandwidth of 1.12 GHz. The two modules are etched on the same substrate in an integrated fashion to give the required structure with two separate feeds and a separation gap between them in the ground plane. The proposed antenna structure is simulated using the CST-MW studio simulator, where it is found that for the mm-Wave module, the band&#x2019;s gain is 5.58 dBi and the efficiency is 0.87 at 25.75 GHz. As for the microwave module, the gain is 2.45 dBi and the efficiency is 0.77 at 5.45 GHz. The proposed structure is implemented practically and the relevant measures agree with the simulated ones. A comparison of the proposed structure with other designs available in literature shows that it exhibits the minimum size among them, while keeping the other parameter values of comparable orders. The proposed structure is suitable for being used in 5G applications where both of the microwave and millimeter- wave bands are utilized.