Multiple-input Multiple-output Structure Research Articles

Design of a compact quad-port wideband printed MIMO antenna for vehicular communication environment

ABSTRACT A wideband quad-port Multiple Input Multiple Output (MIMO) antenna with efficient isolation characteristics for 5 G New Radio (5 G-NR) applications is presented. The proposed antenna works in the span of 3–6 GHz frequency covering the n77/n78/n79 bands also covering the 5 G-V2X band (3300–5000 MHz), LTE-46 band (5150–5925 MHz) and Dedicated Short Range Communication (DSRC) at 5.9 GHz band. The single element of the MIMO antenna structure is modelled by an elliptical structure stacked on a rectangular patch along with the feedline on the conducting plane. The ground plane is modelled as a rhombic design providing a Defected Ground Structure (DGS) to provide the resonance at the desired frequency band. Later, the antenna is evolved as a four-element MIMO system by arranging the antenna elements orthogonal to each other with a distance of separation between the adjacent antenna elements considered to be 10 mm. The all-inclusive dimension of the proposed antenna is 65 × 65 mm2. The simulated MIMO structure is fabricated and measured for antenna parameters and MIMO parameters such as isolation characteristics and MIMO diversity performances. The simulated values are obtained at acceptable limits with the measured values for the proposed wideband frequency range of operation. The compact, wideband antenna is found to be suitable for various 5 G-NR applications, especially Wi-Fi-assisted Vehicular Communication in the sub-6 GHz frequency range.

Photonics-aided exceeding 200-Gb/s wireless data transmission over outdoor long-range 2 × 2 MIMO THz links at 300 GHz

Outdoor long-range terahertz (THz) communications often come at the expense of transmission rate. Moreover, the practicability of the single polarization optical/THz link, which is commonly used in the previous long-range THz demonstrations based on photonics, is extremely limited by the following two fatal defects. One is relying on active polarization control, and the other is not supporting the transparent bridging of optical polarization division multiplexed (PDM) signals for mature coherent optical communication networks. In this work, a large-capacity photonics-aided THz wireless communication system based on the outdoor long-range 2 × 2 multiple-input multiple-output (MIMO) links has been successfully demonstrated. We first build the 200-m 2 × 2 MIMO THz wireless links at the 300 GHz band. The cascaded linear and nonlinear equalizers are proposed which can significantly improve the transmission performance of 100- and 200-Gb/s PDM quadrature phase shift keying (QPSK) signals. Then an interesting 2 × 2 MIMO structure which can provide certain diversity reception gain under 200-m long-range wireless delivery using the same polarization scheme is also presented and further compared with the orthogonal polarization scheme. Since each THz receiver simultaneously receives data from both the two THz transmitters for this MIMO links, an improvement over 6 dB in receiving sensitivity and one order of magnitude in bit error ratio performance under low signal-to-noise ratio conditions can be achieved. Finally, based on the proposed cascaded equalizers and novel 2 × 2 MIMO structure, we successfully demonstrate a record-breaking 58-Gbaud (232-Gb/s) PDM-QPSK signal transmission over 200-m 2 × 2 MIMO THz wireless links. This is an important attempt for the photonics-aided THz wireless communication systems to achieve 2 × 2 MIMO transmission over a long wireless distance in the outdoors. Furthermore, attaining over 200 Gb/s at a wireless distance of 200 m also represents a key milestone for the long-range and large-capacity THz wireless communication systems.

Design and verification of an umbrella shaped narrow band - UWB antenna pair for MIMO applications using characteristic mode analysis

Using characteristic mode analysis (CMA), a pair of ultra-wideband (UWB) and narrow band antennas is made. The Multiple Input Multiple Output (MIMO) configuration incorporates a circular monopole to attain UWB functionality, while an umbrella-shaped element generates the narrowband operation. The two radiators are symmetrically positioned to accomplish space diversity. Distinct sizes of small electromagnetic band gap cells separate the two radiators. The MIMO structure has dimensions of 40×40×1.6 mm3 (0.32λo×0.32λo×0.12 λo) and improved isolation is accomplished by adding a T-shaped stub to the ground plane. The exceptional bandwidth of 11.6 GHz offered by the Circular-pot UWB antenna covers a frequency range from 2.4 GHz to 14 GHz. The antenna demonstrates favorable MIMO performance, featuring a gain of 4.9dBi, isolation exceeding 23 dB. The diversity characteristics encompass an enveloped correlation coefficient (ECC) of under 0.0012, a diversity gain (DG) approaching 10 dB, a channel capacity loss of 0.28 b/s/Hz, and a mean effective gain (MEG) measuring -3.3 dB. A favorable agreement between the tested and simulated results.

On the performance of FSO communication system with WDM and MIMO structure under different turbulent atmospheric conditions

Abstract Free space optical (FSO) communication link is highly weather dependent as the signal passes through the atmospheric channel. The main impairment is atmospheric turbulence, which introduces fading and breakdown the system performance. The performance of FSO link is evaluated in terms of attenuation and link length under different weather conditions. Taking a step further toward the improvement of FSO communication system, wavelength division multiplexing (WDM) is widely used in optical fiber in order to exploit the capacity of a fiber channel more efficiently. Additionally, multiple input multiple output (MIMO) mechanism represents one of the atmospheric mitigation techniques. Thus, integration of MIMO and WDM will provide astonishing results in FSO communication systems. This paper particularly focuses on analyzing the performance of FSO single input single output (FSO-SISO), FSO-WDM, FSO-MIMO, and FSO-WDM-MIMO systems considering different weather conditions. Performance of the different systems has also been compared in terms of received signal power, the quality factor, the bit error rate, and the maximum separation between the transmitter and the receiver for a given received signal level and for various atmospheric conditions. Our results show that increasing the transmitted power and receiver aperture diameter will improve the performance of the system under heavy fog and dense fog.

A Conformal Dual-Band CPW-MIMO Antenna for 5G-V2X Communication

A Co-Planar Waveguide (CPW) fed conformal Multiple Input Multiple Output (MIMO) antenna is presented by deploying circular and rectangular patch in a stacked configuration. The analytical equations for the antenna are modeled and compared with the proposed antenna. The antenna is designed on a flexible polyimide substrate featuring a dielectric value of 3.5 with 0.1 mm thickness resonating at two frequencies, LTE-42 Band (5G-V2X) 3.4-3.6 GHz and Dedicated Short Range Communication (DSRC) 5.850-5.925 GHz. The design is further extended as a 4 × 4 MIMO structure by positioning the antenna elements orthogonal, separated by a distance of 10 mm. The antenna exhibits a reflection coefficient < −10 dB with a gain value between 4.5 and 5.25 dB over the desired frequencies. The radiation efficiency of the antenna is around 90% at both bands. MIMO parameters were measured to analyze the MIMO performance of the proposed antenna and the placement analysis of the antenna is studied by mounting the antenna on various vehicle positions and their corresponding pattern were characterized. The designed MIMO antenna is fabricated and tested, having an overall size of 85 × 85 × 0.1 mm3, offering extremely flexible design functioning to be a promising candidate for next-generation V2X Communication.

Iterative Variational Bayesian Inference Based Channel Estimation for TWR mmWave Systems

Millimeter wave (mmWave) with two way relaying (TWR) is an emerging paradigm towards cellular fifth/sixth generation (5G/6G) technology that can support various data hungry applications with improve coverage, network throughput, and reliability. The foreseen potential of mmWave TWR system can be further alleviated by using large-scale multiple input multiple output (MIMO) architecture. However, high power consumption, hardware complexity and cost of fully digital large-scale MIMO architecture restricts its application. As a countermeasure, hybrid precoding structures with reduced RF chains are utilized. Therefore, the amalgamation of TWR MIMO mmWave system with hybrid precoding structure demands an accurate channel state information (CSI) to avail the maximum gain of two way MIMO communications. Furthermore, the inherent self-interference in TWR systems in collusion with sparse mmWave channels imposes severe challenges in acquiring accurate CSI. The challenge is further aggravated in case of frequency-selective mmWave channel. To solve this problem, we propose a novel iterative variational Bayesian inference (IVBI)-based channel estimation (CE) scheme in the time domain for TWR system with reduced RF chain. In the proposed method, we follow the alternative minimization method involving variational Bayesian inference (VBI) to estimate all the channels of mmWave TWR system. The performance of the proposed algorithm are evaluated over both flat fading and frequency-selective channel. Extensive simulation results for symmetric and non-symmetric MIMO structure validate the proposed algorithm. The Bayesian Cramer-Rao bound (BCRB) of the proposed estimator is also derived. This novel scheme converges fast and achieves significant improvement in terms of normalized mean square error (NMSE) and bit error rate (BER) as compared to state-of-art.

Modeling of quasi-tapered microstrip antenna based on expansion-exponential tapered method and its application for wideband MIMO structure

In this paper, a quasi-tapered wideband antenna using a circular-shaped with an inverted-omega ground structure is presented. A tapered antenna is usually developed based on linear-shape, exponential-shape, or Klopfenstein-shape tapper. Here, we proposed an expansion of the exponential tapered model to investigate the circular-shaped tapered structure. In detail, the proposed antenna is divided into circular divergent and circular convergent-tapered sections. Then, the impedance ratio is utilized to analyze the tapered structure. Moreover, the ABCD parameter based on the transmission line model is used to investigate the overall antenna structure. The proposed model was verified by finite element method and also step impedance resonance evaluation. Furthermore, the proposed wideband antenna is also developed with multiple input multiple output (MIMO) and mutual coupling reduction structure. The antenna was fabricated on a Rogers RT/Duroid 5880 substrate with εr = 2.2, thickness of h = 1.6 mm, and dielectric loss tan d = 0.0009. As a result, the proposed MIMO antenna can successfully cover the 4G (3.3 GHz), mid-band 5G (3.4–3.8 GHz), WLAN (5.8 GHz), X-band (10–11 GHz), and high-band 5G (24.5–26 GHz) communications. A good agreement between the simulated and measured results validates the proposed method.

Phase-Coded FMCW for Coherent MIMO Radar

The phase-coded linear-frequency-modulated continuous-wave (PC-FMCW) waveform with a low sampling processing strategy is studied for coherent multiple-input multiple-output (MIMO) radar. The PC-FMCW MIMO structure, which jointly uses both fast-time and slow-time coding, is proposed to reduce sidelobe levels while preserving high range resolution, unambiguous velocity, good Doppler tolerance, and low sampling needs. The sensing performance and practical aspects of the introduced PC-FMCW MIMO structure are evaluated theoretically and verified experimentally. The numerical simulations and experiments demonstrate that the proposed MIMO keeps the advantages of the linear-frequency-modulated continuous-wave (LFMCW) waveform, including computational efficiency and low sampling demands, while having the ability to provide low sidelobe levels with simultaneous transmission.

Waving Effect Characterization for Water-to-Air Optical Wireless Communication

In this paper, we establish and experimentally verify a water-to-air (W2A) visible light communication (VLC) system through dynamic air-water interface. Considering the complexity of waves in real environments, we divide waves into largescale wave and small-scale wave. Monte Carlo simulation and experimental results show that small-scale wave mainly affects the energy distribution of the light spot on the receiving plane and the variation frequency of link gain, while largescale wave mainly affects the coverage of the light spot. In the W2A-VLC system based on light-emitting diode (LED), the statistical characteristics of variation time and link gain are mainly related to the small-scale wave, and the effect of large-scale wave can be treated as slow fading. In order to design a reliable communication system, a large-divergence-angle LED array and avalanche photodiode (APD) array are used under dynamic water surface. We investigate three cases, namely single-input multiple-output (SIMO), multiple-input single-output (MISO) and multiple-input multiple-output (MIMO). In the SIMO or MISO systems, the correlation coefficient of channel gain decreases with the inter-receiver or inter-transmitter distance. A significant transmission performance enhancement can be achieved by deploying more transmitters or receivers and increasing the distance between the transmitters or receivers. A MIMO structure can effectively increase the achievable rate. We further establish a W2A-VLC link in a deep wave pool to verify our research in the real environment. The results show that more intensive small-scale wave yields higher bit error rate (BER), and the diversity scheme can improve the transmission stability and decrease BER.

Multiband hybrid MIMO DRA for Sub‐6 GHz 5G and WiFi ‐6 applications

This paper inspects a parasitic element-based inverted meandered U-shaped printed line fed hybrid MIMO DRA. The feed of a single element of the 2-elements hybrid MIMO DRA consists of a meandered shaped line coupled to the inverted L-shaped parasitic element printed on the top side of FR-4 substrate with a partial ground on the back. The rectangular-shaped alumina dielectric is placed over the feed to form the single element hybrid DRA. The individual element resonating at 3.40–4.32 GHz (23.83%) and 4.96–5.05 GHz (1.80%) achieves the dual-band characteristics by exciting multiple modes within the rectangular dielectric resonator. The low-profile Multiple Input–Multiple Output (MIMO) antenna configuration having an overall size of 0.57 λ × 0.23 λ × 0.14 λ mm3consists of two orthogonally placed hybrid rectangular DRAs. The inter-element isolation for a connected ground MIMO structure is better than 22 dB in the desired bands of operation without using any isolation improvement techniques. The MIMO diversity parameters are simulated and measured to validate the MIMO performance. The diversity metrics envelope correlation coefficient is below .175, and .15, the mean effective gain ratio is 0 dB, the total active reflection coefficient values are below 15 dB, and channel capacity loss values are below 0.5 bits/sec/Hz in the lower, and upper bands of operation which are within the recommended practical limits. The presented MIMO design achieved the peak gain of 12.87dBi, and minimum radiation efficiency of 83%, with stable radiation characteristics that make the antenna suitable for Sub-6 GHz 5G and WiFi-6 applications.

Design a MIMO printed dipole antenna for 5G sub-band applications

In this paper, a planar multiple input, multiple output (MIMO) dipole antenna for a future sub-6 GHz 5G application is proposed. The planar MIMO structure consists of 4 antenna elements with an overall size of 150×82×1 mm&lt;sup&gt;3&lt;/sup&gt;. The single antenna element is characterized by a size of 32.5×33.7×1 mm&lt;sup&gt;3&lt;/sup&gt; printed on an FR-4 dielectric substrate with εr=4.4 and tanδ=0.02. The suggested antenna structure exhibits good impedance bandwidth equal to 3.24 GHz starting from 3.3 to 6.6 GHz with an S&lt;sub&gt;11&lt;/sub&gt; value of less than -10 dB (S&lt;sub&gt;11&lt;/sub&gt;≤-10 dB) with antenna gain varying from 5.2 up to 7.05 dB in the entire band, which covers all the sub-6 GHz frequency band of the 5G application. Good isolation is achieved between the MIMO elements due to low surface waves inside the MIMO antenna substrate. The radiation of the MIMO antenna structure can be manipulated and many beam-types can be achieved as desired. The high-frequency structure simulator (HFSS) software package is used to design and simulate the proposed structure, while the CST MWS is used to validate the results.

MIMO Radar Design for Extended Target Detection in a Spectrally Crowded Environment

Multiple-input multiple-output (MIMO) radar design for extended targets in a spectrally crowded environment is a challenge owing to the high sensitivity of the target impulse response (TIR) and the increasing requests for spectrum. Assuming unknown TIR, this paper proposes a joint design method to optimize the transmit waveforms and receive filter bank in MIMO structure ensuring spectral compatibility with the overlayed radiators. A priori information is used to impose a spectral constraint on the waveforms, which is the result of a non-convex optimization problem aimed at enhancing the average signal-to-interference-plus-noise-ratio (SINR) over a finite uncertainty set for the TIR. The new method realizes an improved spectral cohabitation with the surrounding radiators through an appropriate modulation of the transmitted energy. In addition, we develop an iterative optimization algorithm which successively enhances the average SINR. Each iteration of the algorithm involves a hidden convex problem, which can be solved resorting to the rank-one decomposition procedure. Finally, the performance is assessed by studying the trade-off among the achieved SINR and spectral shape. The reported results are presented to analyze the performance of the devised method against several counterparts in terms of the SINR value and robustness.

Development of Rogers RT/Duroid 5880 Substrate-Based MIMO Antenna Array for Automotive Radar Applications

In this paper, a novel 2 × 2 multiple-input multiple-output (MIMO) antenna array with four patch elements is designed. The proposed antenna is the first dual band, operating at two prominent working frequencies: 24 (24.286-25.111) GHz and 77 GHz (75.348–79.688), of automotive radars. This structure is composed of two antenna modules colocated on a single substrate, whereas each module is made up of a corporate fed planar array of two elements. This attractive feature enables us to utilize the antenna in two different ways; either both modules serve as the transmitting/receiving antenna of a monostatic radar or one module serves as a transmitter and the other one as the receiver of a bistatic radar. Most of the existing autonomous radar applications operating at 24 GHz are going to become obsolete, and all countries have plans of shifting towards the 77 GHz band. Hence, our design is very attractive as it operates with the required performance in both the bands with another added feature of the MIMO structure. The placement of antenna elements is also optimized in terms of inter- and intraelement separation of greater than λ/2 so as to ensure high diversity gain of 9.6 dBi. Moreover, the proposed antenna structure with only two antenna elements is able to achieve a high gain of around 11.8 dBi and 11.3 dBi at the dual operating modes of 24 GHz and 77 GHz, respectively. In addition to the above-mentioned benefits, this design also addresses mutual coupling reduction that is a common problem in MIMO structures by using complementary split ring resonator (CSRR) structures. State-of-the-art comparison with the recent literature shows that the proposed antenna has less number of antenna elements, an adequate gain, an excellent VSWR value, and high isolation.

Four Element MIMO Antenna Systems with Decoupling Lines for High-Speed 5G Wireless Data Communication

A low-profile planar multiple-input multiple-output (MIMO) antenna consisting of four elements with isolation improvement is proposed for 5G mm Wave (24–40) GHz applications. Each radiating element of the MIMO antenna comprises of a microstrip-fed tilted spade-shaped radiator with four asymmetrical slots and a partial ground plane. The antenna is optimized to resonate at 35 GHz covering a wide impedance bandwidth from 23.9 to 40.1 GHz. Two cross lines are then loaded between the antenna elements to improve the isolation &gt; − 30 d B . The MIMO structure with the decoupling lines is fabricated and tested. The measured results are in good correlation with the simulated results. Other MIMO performance metrics such as the envelope correlation coefficient (ECC), channel capacity loss (CCL), diversity gain (DG), and total active reflection coefficient (TARC) are examined, and the results are found to be satisfactory for the device to be used for mm-wave 5G MIMO applications. Also, the antenna’s performance metrics such as radiation efficiency, gain, and radiation patterns over the operating band are presented.

Opportunistic control of crescent shape MIMO design for lower sub 6 GHz 5G applications

AbstractFor lower sub‐6 5G applications, a two‐element crescent angular ring antenna is proposed. The suggested Multiple‐Input–Multiple‐Output (MIMO) antenna has a dimension of 38 × 25 mm2, a substrate height of 1.6 mm, and dielectric material of FR‐4 (lossy) with a dielectric constant of 4.4 and a loss tangent of 0.002. For 50‐Ω impedance matching, a line feed approach is used to improve return loss and achieve −35 dB at 3.5 GHz. Furthermore, there is a fractional bandwidth from 3–6.5 GHz (116.6%) using a monopole ground plane maintained with |S11| &lt; −10 dB. Changing the placements of the radiators improves isolation by −42 dB. For the current crescent shape, the MIMO structure showed a radiation efficiency and gain of 84.25% and 6.2 dBi. Finally, the performance of MIMO metrics of the crescent shape structure like ECC, diversity gain, channel capacity loss, TARC, and mean effective gain is evaluated in addition to good radiation characteristics.

MIMO Radar Codes/Filter Bank Optimization Design in Clutter Environment

Multiple-input multiple-output (MIMO) radar optimization design for extended targets in clutter is a challenging problem owing to the lack of perfect knowledge of the target impulse response (TIR). Assuming uncertain TIR, this paper focuses on the joint robust design of the radar codes and filter bank in MIMO structure to improve extended target detection capability in signal-dependent interference environment. Considering the average and the worst-case signal to interference plus noise ratio (SINR) at the output as the performance metrics to maximize, we propose two iterative optimization procedures, under similarity and energy requirements on the radar code. The convergence property and asymptotic optimality of two algorithms are analyzed. Finally, simulation results have displayed that two proposed optimization strategies achieve higher objective values than the existing approaches, and share reasonable computational burden.

Terahertz-Band Joint Ultra-Massive MIMO Radar-Communications: Model-Based and Model-Free Hybrid Beamforming

Wireless communications and sensing at terahertz (THz) band are increasingly investigated as promising short-range technologies because of the availability of high operational bandwidth at THz. In order to address the extremely high attenuation at THz, ultra-massive multiple-input multiple-output (MIMO) antenna systems have been proposed for THz communications to compensate propagation losses. However, the cost and power associated with fully digital beamformers of these huge antenna arrays are prohibitive. In this paper, we develop wideband hybrid beamformers based on both model-based and model-free techniques for a new group-of-subarrays (GoSA) ultra-massive MIMO structure in low-THz band. Further, driven by the recent developments to save the spectrum, we propose beamformers for a joint ultra-massive MIMO radar-communications system, wherein the base station serves multi-antenna user equipment (RX), and tracks radar targets by generating multiple beams toward both RX and the targets. We formulate the GoSA beamformer design as an optimization problem to provide a trade-off between the unconstrained communications beamformers and the desired radar beamformers. To mitigate the beam split effect at THz band arising from frequency-independent analog beamformers, we propose a phase correction technique to align the beams of multiple subcarriers toward a single physical direction. To further decrease the ultra-massive MIMO computational complexity and enhance robustness, we also implement deep learning solutions to the proposed model-based hybrid beamformers. Numerical experiments demonstrate that both techniques outperform the conventional approaches in terms of spectral efficiency and radar beampatterns, as well as exhibiting less hardware cost and computation time.

Opportunistic Control of a Slotted Hexagonal MIMO Structure Antenna for Lower Sub-6 GHz 5G Applications

In this research article, a high-performance and compact 2-port slotted hexagonal structure multiple-input multiple-output (MIMO) system is presented. This structure is designed by using novel technology that includes the hexagonal structure with a slotted rotate C-shape structure for obtaining better isolation parameters and commercial 5G applications. The overall design size is 40 × 26 mm2, which is effectively miniaturized at a resonant frequency of 3.5 GHz for a lower sub-6 GHz. Moreover, dual-band characteristics are achieved in the hexagonal MIMO structure by embedding an inverted C-shape structure and monopole rectangular ground planes on the bottom sides of the patches. In addition, the hexagonal MIMO structure shows better diversity performance and high isolation in terms of the Total Active Reflection Coefficient, Envelope Correlation Coefficient, channel capacity loss, mean effective gain, and diversity gain. For the slotted hexagonal MIMO structures established, a better trade-off is achieved and it is found that the MIMO design is the best candidate for applications of wireless communication.

DOA Estimation of a Novel Generalized Nested MIMO Radar with High Degrees of Freedom and Hole-Free Difference Coarray

A novel generalized nested multiple-input multiple-output (MIMO) radar for direction of arrival (DOA) estimation is proposed in this paper. The proposed structure utilizes the extended two-level nested array (ENA) as transmitter and receiver and adjusts the interelement spacing of the receiver with an expanding factor. By optimizing the array element configuration, we can obtain the best number of elements of the transmitter and receiver and the attainable degrees of freedom (DOF). Compared with the existing nested MIMO radar, the proposed MIMO array configuration not only has closed-form expressions for sensors’ positions and the number of maximum DOF, but also significantly improves the array aperture. It is verified that the sum-difference coarray (SDCA) of the proposed nested MIMO radar can get higher DOF without holes. MUSIC algorithm based on Toeplitz matrix reconstruction is employed to prove the rationality and superiority of the proposed MIMO structure.

A Novel Versatile Decoupling Structure and Expedited Inverse-Model-Based Re-Design Procedure for Compact Single-and Dual-Band MIMO Antennas

Multiple-input multiple-output (MIMO) antennas are considered to be the key components of fifth generation (5G) mobile communications. One of the challenges pertinent to the design of highly integrated MIMO structures is to minimize the mutual coupling among the antenna elements. The latter arises from two sources, the coupling in the free space and the coupling currents propagating on a ground plane. In this paper, an array of H-shaped parasitic patches is proposed as a decoupling structure for compact MIMO antennas to reduce propagation of the coupling currents on a shared ground plane. The proposed decoupling structure is generic, and it can be applied to different antenna configurations as demonstrated in the work. Furthermore, it is employed to develop a new high-performance compact dual-band MIMO structure featuring acceptable level of element coupling at both operating frequencies. The design is validated both numerically and experimentally. The mutual coupling levels are less than -17 dB and -20 dB, with the total efficiency of 89% and 90%, and the realized gain of 6.6 dB and 7 dB at the two resonant frequencies of 5 GHz and 6 GHz, respectively. Topological complexity of the compact MIMO systems featuring elaborated decoupling structures, a large number of geometry parameters, as well as the necessity of handling multiple performance figures, constitute the major challenges of antenna design, in particular, its re-design for various specifications. To alleviate these difficulties, the paper also provides a procedure for rapid geometry scaling of the dual-band MIMO antennas. Our approach is based on inverse surrogate modeling methods, and results in numerically-derived expressions that enable a precise control over the operating antenna bands within broad ranges thereof (from 4 GHz to 8 GHz for the lower band, and from 1.1 to 1.3 ratio of the upper to lower operating frequency). The aforementioned procedure is accompanied by an optimization-based design refinement scheme. A practical utility of the procedure is corroborated using multiple verification case studies as well as physical measurements of the antenna designed for the exemplary set of performance specifications.