Single Antenna Element Research Articles

Dual-band dual-truncated R-slot loaded monopole patch antenna using a single-layer bandstop FSS reflector for gain enhancement

New reflector structure (RS) based on ultra-wide stopband single-layer frequency selective structure (FSS) for mid-band sub-6 GHz 5G applications is designed. The proposed RS is arranged into array of 7 × 7-unit cell of FSS elements for antenna gain and front-to-back ratio enhancement. The single antenna element of volume 30 × 20 × 1.6 (in mm3) consists of a dual-quarter-circular truncated edge-fed rectangular slot (R-slot) loaded rectangular patch (R-patch) antenna with degraded ground structure (DGS) to operate at 3.6 GHz mid-band sub-6 GHz 5G and 5.8 GHz WBAN band. The proposed unit cell FSS element, the RS of volume 55.5 × 55.5 × 13.2 (in mm3) and the associated antenna are designed on lossy thin FR-4 substrate material and investigated numerically using commercial computer simulation technology microwave studio (CST-MS) software. The studied dual-structure based RS made with array of single-layer FSS and monopole R-patch antenna is fabricated and measured. The measured impedance bandwidth (IBW) of 48.28% (3.06–4.85 GHz) and 86.20% (5–10 GHz), peak gain of 5.36 and 7.45 dBi, radiation efficiency of 67.11% and 80.16%, and front-to-back ratio of 12.23 dB and 22.84 dB are achieved at the resonant frequencies 3.5 and 5.8 GHz respectively. The FSS reflector associated with the dual-band monopole R-patch antenna performances are in good agreement with the portable wireless applications requirements.

Low-profile, low sidelobe array antenna with ultrawide beam coverage for UAV communication

This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage, low profile, and low Sidelobe Level (SLL) for the application of Unmanned Aerial Vehicle (UAV) air-to-ground communication. The array consists of ten broadside-radiating, ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL. First, an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented. A low-profile, half-mode Microstrip Patch Antenna (MPA) is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole, constructing the compact, end-fire, grounded Huygens source antenna. Then, two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide, broadside-radiating beam. Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance. Experiment indicates an ultrawide Half-Power Beamwidth (HPBW) of 161° and a low SLL of −25 dB with a high gain of 12 dBi under a single-layer configuration. The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.

Unequally-spaced slot strategy for radiation null reduction in single SIW-embedded antenna element

The incorporation of higher-order modes (HOMs) can substantially augment the antenna gain and bandwidth, but this improvement is typically accompanied by compromised radiation performance including radiation nulls and higher side lobe levels. In this study, an inventive strategy is introduced to reduce the radiation nulls and the side lobe levels of a single antenna element by positioning multiple slots of the radiating element at unequal spacing. Dual hybrid HOMs are analyzed inside a substrate integrated waveguide-based cavity to design a wide band, enhanced gain dual-polarized antenna. The radiating element of the antenna is designed with multiple slots positioned at unequal spacing but symmetrical along the origin. This methodology provides three-fold advantages: a reduction of side lobes, an adjustment of phase center, and a significant reduction of radiation nulls. The antenna has been fabricated, and experimentally validated. The antenna exhibits a reduction in radiation null to − 0.5 dB, a phase adjustment of the main lobe to 0°, and a reduction in side lobe level from − 14.4 dB (N = 2, equal spacing) and − 15.5 dB (N = 4, equal spacing) a maximum of − 19.7 dB (N = 4, unequal spacing) at 12.35 GHz in the phi-0 plane. Excellent agreement between measured and simulated results corroborates the efficacy of the proposed approach. The significant improvement in the radiation performance of the single-element antenna design sets the antenna design apart from the state-of-the-art solutions.

Knowledge-based heuristic optimisation technique for mm-wave 5G antenna

ABSTRACT This work presents a knowledge-based decision-making robust antenna design (KDRAD) method that employs a heuristic-optimisation technique for antenna design. The method is used to create and scale a single-element antenna to operate at multiple frequencies within the 5 G range. In this study, a low-profile planar four-element microstrip antenna of 14.8 mm × 14.8 mm × 0.508 mm gives simulated and measured impedance bandwidths of about 1.18 GHz (26.43–27.61 GHz) and 1.08 GHz (26.42–27.50 GHz), respectively, with a centre frequency of 27 GHz. The mm-wave planar four-port antenna has a maximum gain of 7.2 dBi; isolation of 33.2 dB; and multiple antenna matrices with minimal ECC (0.000000109), high diversity gain (10 dB) and channel capacity loss of 0.00110 bits/s/Hz.

A Compact MIMO Antenna Based on Modal Analysis for 5G Wireless Applications.

This article presents a planar, non-angular, series-fed, dual-element dipole array MIMO antenna operating at 28 GHz with the metasurface-based isolation improvement technique. The initial design is a single-element antenna with a dual dipole array which is series-fed. These dipole elements are non-uniform in shape and distance. This dipole antenna results in end-fire radiation. The dipole antenna excites the J1 mode for its operation. Further, with the view to improve channel capacity, the dipole array expands the antenna to a three-element MIMO antenna. In the MIMO antenna structure, the sum of the J1, J2, and J3 modes is excited, causing resonance at 28 GHz. This article also proposes a metasurface structure with wide stopband characteristics at 28 GHz for isolation improvement. The metasurface is composed of rectangle-shaped structures. The defected ground and metasurface structure combination suppresses the surface wave coupling among the MIMO elements. The proposed antenna results in a bandwidth ranging from 26.7 to 29.6 GHz with isolation improvement greater than 21 dB and a gain of 6.3 dBi. The antenna is validated with the diversity parameters of envelope correlation coefficient, diversity gain, and channel capacity loss.

Designing a Novel Hybrid Technique Based on Enhanced Performance Wideband Millimeter-Wave Antenna for Short-Range Communication.

This paper presents the design of a performance-improved 4-port multiple-input-multiple-output (MIMO) antenna proposed for millimeter-wave applications, especially for short-range communication systems. The antenna exhibits compact size, simplified geometry, and low profile along with wide bandwidth, high gain, low coupling, and a low Envelope Correlation Coefficient (ECC). Initially, a single-element antenna was designed by the integration of rectangular and circular patch antennas with slots. The antenna is superimposed on a Roger RT/Duroid 6002 with total dimensions of 17 × 12 × 1.52 mm3. Afterward, a MIMO configuration is formed along with a novel decoupling structure comprising a parasitic patch and a Defected Ground Structure (DGS). The parasitic patch is made up of strip lines with a rectangular box in the center, which is filled with circular rings. On the other side, the DGS is made by a combination of etched slots, resulting in separate ground areas behind each MIMO element. The proposed structure not only reduces coupling from -17.25 to -44 dB but also improves gain from 9.25 to 11.9 dBi while improving the bandwidth from 26.5-30.5 GHz to 25.5-30.5 GHz. Moreover, the MIMO antenna offers good performance while offering strong MIMO performance parameters, including ECC, diversity gain (DG), channel capacity loss (CCL), and mean effective gain (MEG). Furthermore, a state-of-the-art comparison is provided that results in the overperforming results of the proposed antenna system as compared to already published work. The antenna prototype is also fabricated and tested to verify software-generated results obtained from the electromagnetic (EM) tool HFSS.

Pattern Diversity Based Four-Element Dual-band MIMO Patch Antenna for 5G mmWave Communication Networks

This study presents a planar dual-band multiple-input multiple-output (MIMO) antenna design for the prospective fifth-generation (5G) frequency bands of 28 and 38 GHz. The antenna element is designed by utilizing a rectangular patch with an offset microstrip feeding technique. A dual-band response is achieved by placing semi-circular slots on each side of the patch element. To tune the frequency response and improve impedance matching, vertical rectangular slits are etched in the rectangular patch and the ground plane, respectively. The results show that the single antenna element offers an impedance bandwidth of 2.52 GHz (26.32–28.84 GHz) and 7.5 GHz (34–41.5 GHz). In addition, a MIMO configuration based on pattern diversity using four antenna elements is designed and fabricated. The designed MIMO configuration achieves an impedance bandwidth of 3 GHz (27–30 GHz) and 5.46 GHz (35.54–41 GHz) at operating bands of 28 and 38 GHz. The peak realized gain for the single element at 28 and 38 GHz is noted to be 7.4 dBi and 7.5 dBi, respectively. Furthermore, the polarization diversity configuration illustrates an isolation of > 15 dB and > 25 dB for the 28 and 38 GHz frequency bands, respectively. Moreover, the MIMO configuration attains appropriate values for the envelope correlation coefficient (ECC) and diversity gain (DG), Total Active Reflection Co-efficient (TARC), Channel Capacity Loss (CCL) and Mean Effective Gain (MEG) for the operating frequency bands. The proposed MIMO system based on results seems to be potential choice for mmwave Ka Band Applications.

Analysis of antenna arrays using equivalent sources for increase in computational efficiency for 5G and beyond

AbstractThe use of equivalent sources for the analysis of antenna arrays for high computational efficiency has been proposed. A single antenna element has been designed, and the fields have been saved on an enclosed geometry. The surface equivalence principle has been utilized to calculate the far‐field patterns from the fields saved on the enclosed geometry which has been termed as Huygens' box (HB). The antenna element has been used to design , , , and array and the far‐fields have been calculated. For linear arrays of HBs far‐field patterns and computation time have been compared with that of the actual antenna array. As the number of elements increases from 4 to 16, the computation time has been found to reduce from to . Further, the computation time has been found to reduce by and for and configurations, respectively. The method is suitable for analysis of complex geometry of antennas used in 5G technology and beyond.

Broadband unidirectional twin-element MIMO antenna scheme for mid-band 5G and WLAN laptops

This research proposes a broadband unidirectional twin-element multiple-input-multiple-output (MIMO) antenna scheme for mid-band 5G and WLAN applications. The twin-element antenna scheme comprises two single-element antennas, and each single-element antenna consists of a T-shaped hemispherical feeding patch, left- and right-arm radiating patches, and a conjoined triangular ground plane. The twin-element MIMO antenna scheme is integrated with a laptop model functioning as the reflector. The measured impedance bandwidth (|S11|, |S22|≤ − 6 dB) are 55.32%, covering 3.4–6.0 GHz, and the measured mutual coupling (|S12|) is less than − 15 dB. The measured gain at the center frequency (4.5 GHz) is 4.585 dBi. Besides, the measured xz- and yz-plane cross-polarization levels are below − 25 dB and − 15 dB, respectively. The half-power beamwidth (HPBW) in the xz-plane at 3.5, 4.5, and 5.5 GHz are 99°, 92.8°, and 84.2°, and the corresponding HPBW in the yz-plane are 102°, 78°, and 102°. The measured xz- and yz-plane back lobe levels are below − 15 dB across the entire operating frequency band (3.5–5.5 GHz). The radiation pattern of the twin-element MIMO antenna scheme is of unidirectionality. Furthermore, the envelope correlation coefficient and diversity gain of the twin-element antenna scheme are < 0.001 and > 9.99 dB, respectively. The proposed broadband unidirectional twin-element MIMO antenna scheme is thus operationally suitable for mid-band 5G/WLAN communication systems. Essentially, this research is the first to propose a broadband twin-element MIMO antenna scheme for mid-band 5G/WLAN applications.

Isolation enhancement of a two- orthogonal printed elliptical slot MIMO antenna array with EBG structure for millimeter wave 5G applications

This work investigates a high-isolation Orthogonal Printed Elliptical Slot Antenna (OPESA) array with Multiple Inputs and Multiple Outputs (MIMO). A unique composite Electromagnetic Band-Gap (EBG) structure consisting of a vertical six rings positioned between single element antennas were devised and investigated with the aim of reducing mutual interaction between antenna components. A distinct feeble electric field that could successfully inhibit the Mutual Coupling (MC) among the antenna components is easily produced by the suggested composite EBG construction. One type of decoupling constructions throughout the antenna growth was carefully examined at together the theoretical and physical levels in order to offer a clear representation of the suggested antenna array’s design concept and decoupling technique. The antenna array design process was cleverly separated into three stages. In order to verify the suggested decoupling idea, the array Scheme was constructed, assessed, and measured. Studying the antenna gain, radiation pattern, and reflection coefficient, it was found that the simulated and measured findings were very consistent. According to the models, the array has an extreme radiation efficiency of about 91%, a minor value of Envelope Correlation Coefficient (ECC < 1.8 × 10−4), and a maximal gain of 11.5 dBi. The electrical size, highest isolating grade and the recommended MIMO antenna’s 90 dB isolating bandwidth (BW) were assessed. The planned antenna has several appealing features that set it apart from previous similar designs. These features include a low design complexity, a great Diversity Gain rate (DG > 9.99 dB), the BW of the proposed antenna extends from 25 GHz to more than 40 GHz, an enormously great isolation level (about 90 dB), and compressed dimensions (51 mm × 30 × 1.6 mm). For verifying the recommended antenna for MIMO. the suggested MIMO antenna design’s radiation efficiency, a thorough time-domain study is suggested.

Mutual coupling reduction of a two-port MIMO antenna using defected ground structure

In response to the escalating demand for high data rates and the expanding user base, multiple input multiple output (MIMO) technology has recently become of paramount importance in addressing the imperative for high-capacity communication systems aligned with emerging standards. In this paper, a single antenna element that achieves a wideband frequency coverage by adjusting the slots ‘dimensions and a satisfactory gain of 6.4 dBi is presented. To enhance the antenna's gain and capabilities, we introduced a MIMO antenna designed to operate within the frequency range of 36.8 to 40.9 GHz. The proposed MIMO antenna configuration consists of two-element arrays etched on a compact 25.94×26.76×1.3 mm³ Rogers RT/duroid 5880 substrate. While maintaining the operational band and enhancing gain, a critical challenge involving inadequate isolation between the two antenna elements is encountered due to the confined area. To effectively tackle this issue, a parametric study on the inter element distance between antennas is conducted and Defected Ground Structure (DGS) is implemented. This refinement results in a substantial 3.6 dB enhancement in isolation, which is found to be lower than -31 dB, a notable improvement in impedance matching, and a remarkable high gain of approximately 7.7 dBi is achieved. Besides, the analysis of the MIMO metrics demonstrates that they consistently fall within acceptable ranges, with the antenna showcasing an envelope correlation coefficient of approximately 0.005 and a commendable diversity gain of around 9.99 dB. The proposed antenna's combined attributes, including its compact, simple, and low-profile design, position it as a highly promising choice for 5 G communication system and future miniature devices intended for Internet of Things (IoT) applications.

Characteristic mode based self isolated MIMO antenna design for millimeter wave 5G communications

The paper introduces a self-isolated quad-port multi input multi output antenna system designed for fifth-generation wireless communication. The reported antenna structure possesses an overall dimension of 12.4 × 12.4 × 0.508 mm3 and is derived from a single-element antenna, featuring a circular patch accompanied by a sectoral slot. To achieve the desired frequency band, an additional circular patch is purposefully placed over the main radiator. The development of each design stage in the antenna structure is investigated using the theory of characteristic mode. This configured multi-element antenna structure achieves a broad operational bandwidth spanning 4.5 GHz, encompassing frequencies from 26.1 GHz to 30.6 GHz, rendering the antenna well-suited for deployment in the millimeter-wave frequency bands of n257, n258, and n261 respectively. A total gain of 6.27 dBi is achieved with port isolation of −24 dB. Furthermore, the antenna undergoes validation for diversity metrics, including envelope correlation coefficient, diversity gain, channel capacity loss, total active reflection coefficient, and mean effective gain. The antenna is fabricated and experimentally validated with the simulated counterpart. Later, a comparative analysis has been conducted which revealed that the proposed antenna demonstrates > 80 % increase in compactness compared to existing antenna designs documented in the literature.

Design and Simulation of a High Performance 5G mm-Wave MIMO Antenna Array for Mobile Applications

This paper presents the design and simulation of an efficient multiple input multiple output (MIMO) antenna array for 5G millimeter-wave (mm-wave) mobile applications. With a dielectric constant of 2.2 and a loss tangent of 0.0009, the substrate employed is a Rogers RT5880 that is 0.254 mm thick. The 37 GHz frequency spectrum, reserved for millimeter-wave mobile applications for 5G, is covered by the proposed MIMO antenna arrays. The single antenna element has a gain of 6.44 dBi, which is increased to 7.89 dBi with a two-element array configuration and 10.88 dBi with a four-element array configuration. The proposed MIMO antenna array performance metrics—including reflection coefficient, VSWR, radiation efficiency, and gain—are seen and discovered to be below the accepted threshold. In the desired operating frequency band, it is noticed that more than 85% of the proposed MIMO antenna array's radiation efficiency is achieved. According to simulation findings, the proposed design may be potentially feasible for mobile applications using millimeter waves in the 5G network.

Dual-Notched UWB Orthogonal MIMO Antenna with Improved Gain Characteristics Using Frequency Selective Surfaces for Wireless Communication Applications

In this paper, a complementary split ring resonator (CSRR) loaded compact CPW-fed circular shaped monopole UWB antenna with dual band notch characteristics is designed on an FR-4 substrate. The propounded band-notched UWB antenna is integrated with two frequency selective surface layers referred as bandpass frequency selective surface (FSS-1) and reflector (FSS-2) to offer enhanced radiation performance. Bandpass FSS-1 enhances the gain of the antenna by improving directivity and reflector FSS-2 reflects back the backside radiation of the proposed antenna towards the forward direction thereby increasing gain and directivity of the proposed antenna. Furthermore, a two-element orthogonal MIMO antenna is proposed with improved gain using two FSS layers. The complete configuration of the proposed two-element MIMO antenna consists of CSRR-based radiating patches, monopole ground planes and two integrated FSS layers. The proposed MIMO antenna operates in UWB range from 3.46[Formula: see text]GHz to 16.02[Formula: see text]GHz with dual notches at 3.9[Formula: see text]GHz and 7.2[Formula: see text]GHz. Isolation between MIMO elements is greater than 23 dB. Both antennas are fabricated and investigated at 5.9[Formula: see text]GHz for vehicular communications. Maximum gain improvements of 8 dB and 6.4 dB are observed in case of the presented single element and MIMO antenna within the entire operating band due to the integration of dual FSS layers. The diversity performance of the suggested MIMO antenna is investigated by analyzing mean effective gain, envelope correlation coefficient, channel capacity loss and diversity gain parameters. The proposed MIMO antenna is a suitable candidate for vehicular and UWB wireless communication applications.

Linear Phased Metamaterial Incorporated Patch Antenna Array at 28 GHz for 5G Base Stations

This article presents a 1×6 linear phased antenna array implemented with metamaterial incorporated patch antennas for 5G base stations. The single element antenna was modelled on Rogers RT/duroid 5880 substrate in the dimensions of 7.8×7.8×0.254 mm3 with metamaterial incorporated partial ground plane and complementary metamaterial incorporated patch. This metamaterial incorporated antenna structure is resonating in 22.03–33.55 GHz at central frequency of 28 GHz with 40% impedance bandwidth with respect to the –10 dB return losses. With aim to design a radiating structure for 5G base stations and in order to enhance the gain, a six element phased array was developed using the abovementioned single element antenna with inter element spacing 7.8 mm between the adjacent antenna elements. In the analysis of this phased array, we observed acceptable diversity parameters (isolation, ECC, DG, CCL, and MEG) and presented beam steering capabilities by changing the phase difference between the adjacent ports. The proposed six element phased array antenna is capable to steer the beam to ±43.5° and capable to cover 5G NR n-257, n-258 and n-261 bands with significant gain and efficiency.

Compact Sub-6 GHz Four-Element Flexible Antenna for 5G Applications

This paper proposes the design of a compact sub-6 GHz four-port flexible antenna for utilization in 5G applications. A two-arm monopole with a coplanar waveguide feed line printed on a flexible substrate was proposed to shape the single-element antenna. The single element was designed, fabricated, and measured first; then, four copies of the single element were organized on a single flexible substrate to compose the four-port antenna. The MIMO antenna was simulated, fabricated, and experimentally measured. All the simulations and measurements of the flexible single element and MIMO antennas are presented. The presented MIMO antenna showed good impedance characteristics, with a deep level of −24 dB from 3 to 4.12 GHz. The antenna had omnidirectional and bi-directional patterns in the φ = 0° and φ = 90° planes. As an important parameter evaluation for MIMO, the mutual coupling between the different ports was investigated. The diversity gain (DG), the total active reflection coefficient (TARC), the mean effective gain (MEG), the envelop correlation coefficient (ECC), and the channel capacity loss (CCL) parameters were investigated and showed good performance. All the obtained simulation results were in a high degree of agreement with the measurement results, supporting the usage of the suggested antenna in 5G communications.

SMALL-SCALE MIMO ANTENNA WITH HIGH ISOLATION FOR 5G COMMUNICATION

This manuscript describes two- and three-element small-scale multiple-input multiple-output (MIMO) antenna configurations for 5G communications ranging from 23.5 to 28.6 GHz. Modern device antennas have two essential features: isolation and a larger bandwidth. In this regard, firstly a single element antenna has been designed using quarter wavelength impedance transformer and semi-circular loaded patch along with defected ground structure. Furthermore, two single-element antennas are placed orthonormal to each other having quarter wavelength distance from the center of the single-element antenna. To increase the bandwidth and isolation, additionally a rectangular patch and strip isolate from ground. This structural change alters the current path, improving the impedance matching and isolation of the two-element MIMO antenna configuration. After that the three-element MIMO configuration was formed by placing two single-element antennas orthogonally at quarter wavelength from the center of the single-element antenna. The total size of two- and three-element MIMO antenna is 15 &amp;times; 11 &amp;times; 1.6 mm and 20 &amp;times; 11 &amp;times; 1.6 mm, respectively. The proposed MIMO antennas provide isolation of more than 21 dB and gain more than 25 dB throughout the working band. MIMO diversity features function reasonably well, with an envelope correlation coefficient of less than 0.002 and diversity gain of 10. Proposed antennas can be a good candidate for MIMO applications in the 5G communication frequency range 2 (FR2), 28 GHz bands.

Design of a 2*2 Microstrip Phased Array Antenna for Radar Applications

Micro-strips patch antennae used in array configurations are more beneficial than single antenna element by augmenting the directivity (dB) radiation pattern, and lowering the substrate's permittivity to overcome its drawbacks, which include poor gain, low efficiency, narrow bandwidth limited directivity. It also facilitates beam-steering capability which is obtained by enabling phase difference(β) between the antennas. Beam scanning capability is used in radar and GNSS technologies. This paper proposes a 2*2 microstrip phased array antenna by using rectangular microstrip patch antenna on an FR-4 dielectric substrate for beam scanning. The resonant frequency of the antenna is at 2.52GHz frequency with a good Voltage Standing Wave Ratio (VSWR) value of 1.1325. The design has been simulated in Ansys HFSS software. The simulation results exhibit antenna better performance of the proposed antenna compared to state-of-art designs present in the literature. The compactly designed Rectangular Micro-strip Patch Antenna array shows a low S-parameter (–24.127858 dB), high gain (13.689104 dB), directivity (14.055125 dB), and efficiency of 91.917%.

Dual Band 1x4 Linear Metamaterial Bowtie Antenna Array for Autonomous Vehicle in Public Safety Band Communications

This research presents the design, simulation, and fabrication of a dual-band 1x4 linear metamaterial bowtie antenna array for applications in 5G wireless systems and public safety band communications. The single-element antenna is a compact dual-band structure with a complementary split-ring resonator (TCSRR) element, and it exhibits resonant frequencies of 3.5 GHz and 4.9 GHz, covering the sub-6GHz 5G spectrum and the public safety band. The antenna aray design is optimized for impedance matching and radiation efficiency. The 1x4 linear antenna array is designed with a quarter-wave transformer feed network and carefully controlled mutual coupling to enhance gain and directionality. Simulated and measured results confirm the performance of the array, with a reflection coefficient within -10 dB from 3.2 GHz to 3.85 GHz and from 4.55 GHz to 5.95 GHz and 3.45 GHz to 3.75 GHz and 4.45 GHz to 5.7 GHz, respectively. The array exhibits a peak realized gain of up to 8.7 dBi and efficient radiation patterns. This work offers promising insights into the development of antenna systems for advanced wireless communication applications and vehicle-to-vehicle communication in public safety band.

CSRR loaded multiband THz MIMO antenna for nano-communications and bio-sensing applications

In this paper, a multiband THz Multi-Input Multi-Output (MIMO) antenna is designed with dimensions of 80×100×10.8μm³. The antenna is made-up on a gold-plated Arlon AD410 substrate with a relative permittivity of 4.1.It operates at three resonant frequencies, namely 1.45THz, 2.25THz, and 3.25THz, achieved through the integration of Complementary Split-Ring Resonator (CSRR) and Substrate Integrated Waveguide (SIW) technologies. The two-element MIMO configuration of the antenna ensures exceptional performance, offering high throughput with data rates of 25.23Gbps for the Quadrature Phase Shift Keying (QPSK) scheme and 56.68Gbps for the 16-Quadrature Amplitude Modulation (QAM) scheme. It also exhibits remarkable channel capacity, approximately 8.2bps/Hz at Signal-to-Noise Ratio (SNR) = 20dB, surpassing the capabilities of single-element antennas. Moreover, it demonstrates excellent diversity performance for judging the MIMO antenna performance. This is evident through the following key metrics: Envelope Correlation Coefficient (ECC) < 0.02, indicating that less than 1 % of power is transferred from the excited antenna to the second 50Ω terminated antenna when antenna-1 is excited; Directive Gain (DG) >9.95dB; Total Active Reflection Coefficient (TARC) < -10dB, ensuring that a minimum of 90 % of the power is delivered to the patch port; and Channel Capacity Loss (CCL) < 0.35 bits/sec/Hz, guaranteeing reliable wireless communication. The antenna boasts peak gains of 3.83dBi, 4.06dBi, and 6.82dBi at 1.45THz, 2.25THz, and 3.25THz, respectively, along with a radiation efficiency of approximately 37, 58, and 51 % at the corresponding frequencies. Notably, the first two bands (1.34-1.51THz and 2.20-2.28THz) exhibit narrow bandwidths with quality factors above 80, making them particularly suitable for sensing applications in biomedical. Band-1 offers an average sensitivity of 3222.22 GHz/RIU and an FOM of 17.89, while Band-2 provides an average sensitivity of 2578.68 GHz/RIU and an FOM of 14.38. These characteristics make it well-suited for near-field Nano-communications and sensing applications.