Monopole Slot Research Articles

Compact dual-band dual sense circularly polarized flexible antenna with polarization rotation metasurface for off-body communications

ABSTRACT A dual-band dual circularly polarised flexible antenna, operating at 3.5 GHz for WiMAX and 5.8 GHz for industrial, scientific, and medical (ISM) bands, is proposed for wearable applications. The antenna design integrates a wideband comb-shaped slotted monopole antenna with a polarisation rotation metasurface (PRMF). The PRMF unit cell consists of a nested split square ring in the corner and a square ring in the centre, where the split square rings facilitate polarisation conversion and the centre square ring enhances the axial ratio. The PRMF integration helps achieve dual circular polarisation (CP) radiation, with left-handed CP in the WiMAX band and right-handed CP in the ISM band. The proposed monopole antenna and PRMF are printed on a conformal polyimide substrate, with a total footprint of 48 × 48 mm2 (0.31λo2). The proposed antenna has a 10 dB impedance bandwidth of 24.9% (3.2 to 4.2 GHz) and 18.9% (5.3 to 6.43 GHz), a 3-dB axial ratio bandwidth of 11.1% and 21.4%, and a peak gain of 6.4 and 6.7 dBic in both bands. Numerical and measured results demonstrate that the antenna performs well in the presence of human body and structural deformations. These attributes make the proposed design highly suitable for off-body wearable applications.

A Novel FSS Loaded Circular Slot Monopole Antenna for Microwave Breast Imaging Application

Breast cancer continues to be a major contributor to women's global mortality rates, emphasizing the need to explore alternative and supplementary early-stage detection techniques. This study delves into a circular slot monopole ultra-wideband (UWB) antenna equipped with a frequency-selective surface (CSMA-FSS) for early detection microwave imaging applications. To expand the impedance bandwidth of the traditional circular monopole antenna, a circular slit is introduced on a monopole structure. Additionally, a 10 × 10 unit cell FSS structure is integrated into the antenna as a far-field reflecting plane to enhance gain characteristics. The antenna, crafted with dimensions of 50 × 50 × 1.6 mm³ and a 1.6 mm thick FR4 substrate, operates across the ultra-wideband frequency spectrum, spanning from 3.1 GHz to 12 GHz, while consistently maintaining a reflection coefficient (S 11) value of – 10 dB or lower. Notably, the antenna showcases a gain of over 5 dBi across the entire 3.1 GHz to 12 GHz frequency range. The suggested antenna is ideal for microwave imaging applications due to its broad impedance bandwidth, impressive gain, and excellent directivity. Furthermore, it maintains a relatively uniform group delay, with a deviation of ±0.5 ns throughout the UWB band. In the time domain characteristics, the antenna exhibits excellent pulse handling capabilities and strong signal correlation, featuring an S 21 value of less than – 25 dB. The characteristics, observed in both the time and frequency domains, suggest that the proposed antenna holds significant potential for substantially enhancing breast cancer imaging system.

A dual-port, single-fed, integrated microwave and mm-wave MIMO antenna system with parasitic decoupling mechanism for 5G-enabled IoT applications

The integration of microwave and mm-wave antenna is recognized as a promising solution to ensure backward compatibility while effectively utilizing available space for 5G-enabled modern IoT devices. This paper proposed a very compact size multi-band dual-port MIMO antenna module, aiming to provide complete coverage in microwave frequency bands, including 2.4 GHz, 3.5 GHz, 5.3 GHz, and 7.5 GHz, along with 5G mm-wave bands such as 28 GHz. This is achieved through a common feedline by incorporating a semi-circular slotted monopole with strategically positioned quarter-wavelength metallic stubs on a partial ground plane. The proposed antenna exhibited -10 dB impedance bandwidths of 22.6% (2.16–2.71 GHz), 17.9% (3.36–4.02 GHz), 9.4% (5.18–5.69 GHz), 15.9% (7.29–8.55 GHz), and 15.5% (26.02–30.39 GHz) across diverse frequency bands. To attain compactness and high isolation capabilities, a composite three-dimensional parasitic element is employed as a decoupling structure to alleviate significant interference among closely positioned radiating elements. The proposed antenna provides radiation efficiency of > 85%, achieving necessary peak gains of 2.32 dBi, 3.46 dBi, 4.15 dBi, and 5.32 dBi at respective microwave frequencies. While in mm-wave frequency bands, radiation efficiency exceeds 95% having a measured realized gain of 6.2 dBi at 28 GHz. The proposed design successfully maintains an average isolation of > 28 dB in all frequency bands. The suggested MIMO configuration demonstrates outstanding diversity performance, which is evidenced by ECC, DG, MEG, CCL, and TARC.

A 0.18 μm CMOS Millimeter Wave Antenna-on-Chip with Artificial Magnetic Conductor Design

This paper presents a small-size broadband slot monopole chip antenna for millimeter wave application. Using a 0.18 μm CMOS process, through metal_1, the artificial magnetic conductor (AMC) of the metal layer increased the impedance bandwidth of the chip antenna. The additional inverted C branch was used to achieve a better reflection coefficient. By adding an AMC and inverted C branch, the operating frequency of the chip antenna went to 33.8–110 GHz below the reflection coefficient of −10 dB, and its fractional bandwidth was 103.4%. The maximum gain was −6.3 dBi at 72 GHz. The overall chip size was 1.2 × 1.2 (mm2). Through measurement and verification, the proposed antenna reflection coefficient was close to the simulation trend and had better resonance. The frequency range of the chip antenna proposed in this paper covered the 5G NR FR2 band (24.2 GHz–52.6 GHz) and W-band (75 GHz–110 GHz). The proposed chip antenna can be applied to the Internet of Things, Industry 4.0, biomedical electronics, near field sensing and other related fields.

English

In this paper, a pentagon-shaped slotted monopole antenna for WIFI6E applications based on a partial ground structure is designed, and its performance is evaluated. The pentagon-shaped slotted antenna has a dimension of 44 × 36 × 1.6 mm3 and exhibits good radiation characteristics most suitable for wifi6E applications. The designed structure is fabricated on FR4 high dielectric substrate material to evaluate the antenna characteristics. Four arc slots are removed from the pentagon patch to resonate at wideband frequencies. Simulation has been done in ANSYS HFSS SOFTWARE 19v. A peak gain of 6.2 dBi is attained by the pentagon-shaped slotted antenna, and the antenna produces a bi-directional radiation pattern.

Design and analysis of compact flower-shaped wideband slotted monopole antenna for RFID reader applications

This article introduces the design and analysis of a compact, high gain, and wide bandwidth flower-shaped slotted monopole antenna for RFID reader antenna applications. The proposed antenna comprises a flower-shaped radiator with six arc-shaped slots and a partial ground plane. The measurement results indicate a wide operating band in the frequency range of 2.4 GHz–7.6 GHz. The proposed antenna is designed to operate at 5.8 GHz ISM band for RFID reader applications with a peak measured gain of 3.9 dBi. The structure has an overall dimension of 0.78λ× 0.58λ× 0.03λ at an operating frequency of 5.8 GHz and is found compact in comparison to some related designs. The monopole antenna shows an omnidirectional radiation pattern in the operating band and indicates a maximum realized gain value of 4.2 dBi. The study provides a detailed mathematical analysis of the operating principle with surface current distribution plots. The design indicates a reading range of 2.56 cm at 5.8 GHz and the satisfaction of the propagation-test makes the compact, wideband, and high-performance design suitable for different short-range RFID reader applications.

Design of the Composite Fractal Embedded Slot Monopole Antenna

In this paper, the rectangular nested fractal and Cantor fractal slot are skillfully fused together, and the composite fractal embedded slot radiation structure is creatively designed. It combines the microstrip monopole antenna of high radiation intensity and excellent directional radiation capability with the microstrip Balun feed structure of wide frequency range and step-by-step impedance matching capability to design composite fractal embedded slot monopole antenna that can meet the performance requirements of BeiDou Navigation Satellite System. Actual test results show that the antenna has the advantages of both a high-performance redundant antenna and a directional radiation antenna and can completely cover the BeiDou Navigation Satellite System working for the frequency band. It is a high-performance satellite positioning antenna with strong application potential.

Dual-Band Millimeter Wave 2 × 2 MIMO Slot Antenna with Low Mutual Coupling for 5G Networks

A dual-band 28/38 GHz multiple-input multiple-output (MIMO) two elements antenna for the next 5G network is proposed in this paper. The single element is composed of a slot monopole antenna loaded with stub and a small crescent with an entire size of 15 × 15 mm2. The two elements are added to compose the suggested configuration. One of the antennas is printed on the upper layer while the other is located on it's back of the substrate to improve the coupling between elements without using any decoupling structures. The innovative antenna of dual-band works at 28/38 GHz and is achieved by adjusting the stub length and the crescent radius. The introduced MIMO antenna system has been experimented and the results have the same compatible trace with the simulated outcomes. The proposed two ports MIMO achieved a reasonable gain that reaches 5.7 and 6.9 dBi in the 28/38 GHz bands, respectively. The proposed MIMO antenna performance is also analyzed and achieved the envelope correlation coefficient, a diversity gain, and channel capacity Loss of about 10–4, 10 dB, and less than 0.3 bit/s/Hz, respectively over the 28/38 GHz bands. Finally, from the simulated and measured outcomes, it can be confirmed that the suggested MIMO antenna system can be applied to 5G wireless telecommunication applications.

Triple-band stub loaded patch antenna with high gain for 5G Sub-6 GHz, WLAN and WiMAX applications using DGS

Microstrip antennas have become ubiquitous in today's wireless communication world due to their low profile, low cost, and simplicity in fabricating on circuit boards. However, poor performance characteristics, such as limited bandwidth, low power handling capabilities, and low gain, limit their applicability in various instances. Path loss will be substantial in 5th generation (5G) wireless communication due to the utilization of high-frequency bands. A high-gain antenna with a small size is necessary to address this issue. A compact tri-band, slotted monopole antenna with high and consistent gain employing a defected ground plane structure (DGS) has been investigated and implemented in this study. This proposed antenna uses three inverted L-shaped stubs connected to the radiating element to cover the desired bands while keeping the antenna size small. The designed antenna has two key characteristics: (i) wide bandwidth and (ii) reasonable gain. The antenna covers 2.45 and 5.6 GHz WLAN, 2.4 GHz Wi-Fi, 2.5 and 5.2 GHz WiMAX and 3.7 GHz Sub-6 GHz of 5G for mobile communication. The overall substrate size of the antenna is 30 ? 17 ? 1.6 mm3and the electrical dimensions are 0.49 ?L ? 0.28 ?L ? 0.026 ?L, where ?L is the free space wavelength at 2.45 GHz. The measured reflection coefficient (S11 < -10dB) covers 2.4 - 2.52 GHz (bandwidth 112 MHz) and 3.4 - 4.1 GHz (bandwidth 700 MHz) and 5.2 - 6.6 GHz (bandwidth 1359 MHz) with a fractional bandwidth of 5.1 % at lower frequency band, 18.6 % at mid frequency band and 23.7 % at high frequency band. A prototype antenna has also been developed using an inexpensive, low-profile 1.6 mm thick FR-4 (?r = 4.4) substrate. The measured peak gains achieved are 1.35 dB at 2.45 GHz, 2.55 dB at 2.65 GHz and 3.8 dB at 5.5 GHz. The simulated results have been validated against actual experimental measurements, and the outcomes are consistent and match with certainty. The proposed antenna design is very compact and easy to fabricate due to the absence of vias.

Compact tunable terahertz self-diplexing antenna with high isolation

A tunable terahertz (THz) slotted monopole antenna is implemented with self-diplexing capability. The radiating arms of antenna are filled with the graphene strips. The variation in electrical parameters of graphene alters the surface current distribution in the radiating arms which results in tuning the antenna response through individual input ports. Antenna operates in frequency range 4.75–5.34 THz and 5.57–6.76THz with the application of input at port-1 and 2, respectively which can further be tuned with the reported biasing schemes. The antenna structure utilizes the orthogonal radiating slots which provides high isolation more than 150 dB between the ports in compact antenna geometry. An electrical equivalent circuit is prepared to verify the antenna operation. In addition, antenna offers the peak gain 3.83 dBi at port-1 and 6.06 dBi at port-2 in the operating passband along with the efficiency of more than 80%. Antenna provides the compact geometry with tunable self-diplexing capability and can be suitable for future wireless applications requiring the simultaneous transmit and receive systems.

A novel broadband monopole coplanar antenna configuration with circular polarization

In this paper, a novel construction of a wideband slotted monopole antenna supplied by a single coplanar waveguide (CPW) with circular polarization (CP) characteristic for the small wireless device is proposed and discussed. The circular polarized CPW antenna is intended for the Industrial Scientific Medical (ISM) band spanning at 2.45 GHz. It consists of a monopole-shaped patch with two oppositely facing corner gaps extending from the CPW signal strip into the middle of a square metal frame serving as the ground, incorporates a couple of L-shaped grounding strips surrounding two oppositely facing corners of the ground, and an L slot in the topside of the ground plane. The bandwidth of the antenna’s input impedance is widened through reconfiguring the necessary parameters of the reversed L-shaped grounding strips. The circularly polarization can be significantly achieved through cutting an upturned L-slot mostly in the topmost half of the ground. The proposed antenna has a size of 60600.74mm3. Two electromagnetic solvers have been used to examine and to optimize the proposed circuit. The final circuit of the circularly polarized CPW monopole antenna is fabricated and validated by measurements. The measured bandwidth concerning the return loss at -10 dB is about 1.30 GHz and for the axial ratio at 3 dB, it’s about 500 MHz.

A scanning phased array based on a polarization reconfigurable antenna with compact aperture size

A compact antenna with tri-polarization switching is presented. The antenna is mainly composed of a monopole slot and a shorted loop, and the two radiating elements are connected in series and placed in a metallic box filled with dielectrics. To realize polarization switching, four PIN diodes are introduced into the antenna structure, and they cannot only suppress the excitation of the loop antenna but also vary the direction of the current flowing on the loop. Both simulated and measured results indicate that the proposed antenna can be operated in one linear polarization and dual circular polarization modes within an impedance bandwidth of around 15%; moreover, the aperture size of the antenna is about 0.09 λ02. Based on the polarization reconfigurable antenna, a 1 × 8 phased array with an aperture size of 0.3 λ0 × 2.8 λ0 is then developed. Simulated results show that the phased array operating in each polarization mode can give a gain fluctuation of smaller than 1.5 dB and a side lobe level of less than −10 dB when the beam is scanned from −60° to 60°. Experiments are also carried out, and their results have good agreements with the simulated data.

Efficient and optimized six- port MIMO antenna system for 5G smartphones

AbstractIn this paper, six-port MIMO antenna is presented for 5G mobile handsets. The proposed six-port antenna array is designed by making four L shaped monopole slots at four corners and two at the middle side edges of the ground plane which is printed on the backside of 0.8 mm thick FR4 substrate. High isolation (>−18 dB) between any pair of antenna elements is achieved without deploying dedicated isolation enhancing mechanisms. The antenna is working from 3.4–3.6 GHz (LTE Band 42) with 200 MHz bandwidth in the 2:1 VSWR (−10 dB impedance bandwidth). The proposed six-port MIMO antenna array is fabricated and measured. Significant radiation efficiency is obtained from 70 to 74 % in desired band of operation. Further, the MIMO parameters such as Envelope Correlation Co-efficient (ECC), Channel Capacity, Channel Capacity Loss (CLL) and Total Active Reflection Co-Efficient (TARC) are calculated. The robustness of the antenna is estimated by analyzing the user hand effects and Specific Absorption Rate (SAR). The measured results are well agreed with the simulated results.

Performance Analysis of Highly Efficient Two-Port MIMO Antenna for 5G Wearable Applications

In this paper, a compact low-profile dual-band 2 × 2 wide band wearable slot antenna (smart watch) for the frequency spectrum of 3.4–3.6 GHz (LTE Band 42) is proposed. For smart watch applications, the antenna should be as small as possible and it should be resonating at the forthcoming 5G technology. Hence, two resonant modes are achieved for each antenna by etching the T-shaped monopole slot in the ground plane of size 40 × 40 mm2, and each slot is coupled fed by the L-shaped tuned stub which is printed on the 0.8 mm-thick FR4 substrate. The proposed antenna is fabricated and its performance is experimentally measured. The measured antenna parameters agree well with the simulated results. The reflection co-efficient and transmission co-efficient of the Multi Input Multi Output (MIMO) antenna are well below −10 dB throughout the band of operation. The efficiency of the MIMO antenna is achieved up to 81% with the overall gain of about 2.4 dB. To validate the proposed MIMO performance, the envelope correlation co-efficient between the antenna elements is calculated. In this paper, the effect of the proposed antenna in the human hand is also studied and discussed along with the specific absorption rate.

Circular Slotted Antenna with CPW feed for GSM and UWB Applications

Background & Objective: The circular slotted monopole microstrip antenna with Coplanar Waveguide (CPW) feed for unified GSM and Ultra-Wideband (UWB) applications have been presented in this article. Circular shaped slots have been embedded in the radiating patch. Less surface area has been found due to slots etching and the overall antenna size is reduced by 45%. Result: The proposed antenna demonstrates a double band operation wrapping 883.6-1206 MHz (GSM band) and 2.75-18.30 GHz (UWB, X, and Ku) frequency band with VSWR of less than 2 and fractional B. W. of 30.8 % and 147% respectively. The pattern of radiation presented by the antenna is nearly omnidirectional in H-plane and directional in E-plane within the GSM and UWB band. Conclusion: There is a variety of applications nowadays using these UWB antennas such as modern civil and military applications, wireless and radar communications, etc. Measured results are presented to validate the proposed antenna structure, which shows that the proposed designed antenna structure has a stable radiation pattern both at the GSM and UWB band ranges.

Planar Multi-broadband Antenna for LTE/5G/GPS/GSM/UMTS and WLAN/WiMAX Wireless Applications

In this paper, a simple planar multiband antenna design for wireless handsets is introduced. The proposed antenna can support four broad frequency bands, covering LTE/WWAN/GNSS/WiMAX/WLAN and several bands that are suggested for 5G systems. The proposed antenna design consists of a folded driven monopole strip, and a parasitic ground connected to the main ground with several etched slots on the ground plane. The parasitic ground in conjunction with the driven monopole slot helps to cover the lower band, including LTE700 and GSM bands, while the slots at the parasitic ground help to fully cover and tune other desired bands. The antenna is printed on a low-cost ultra-thin FR-4 substrate with a compact size of 135 mm $$\times$$ 60 mm $$\times$$ 0.5 mm, suitable for the state-of-the-art wireless handsets, such as smart-phones. The design procedure and measurement results of the antenna have been presented and discussed.

Performance Analysis of Slotted Monopole Antenna with Pin Diodes for Wireless Applications

This paper deals with Performance Analysis of slotted monopole antenna with pin diodes for wireless applications. The antenna is designed on a 1.6 mm thick FR4 substrate with the dielectric constant ( ) of 4.4. Antenna is electrically reconfigured incorporating pin diodes as switching elements to tune desired frequency and to achieve frequency reconfigurability. The antenna parameters like return loss, bandwidth, radiation pattern, directivity and gain are simulated and characterized in this paper. The proposed antenna covers resonating frequencies ranging from the 3.7-13.4GHz. The proposed microstrip monopole frequency reconfigurable antenna can be considered as electrically small, low weight, low profile. The design and analysis of the proposed antenna is accomplished through HFSS EM simulator.

COMPACT UWB SLOTTED MONOPOLE ANTENNA WITH DIPLEXER FOR SIMULTANEOUS MICROWAVE ENERGY HARVESTING AND DATA COMMUNICATION APPLICATIONS

COMPACT UWB SLOTTED MONOPOLE ANTENNA WITH DIPLEXER FOR SIMULTANEOUS MICROWAVE ENERGY HARVESTING AND DATA COMMUNICATION APPLICATIONS

Triple notch slotted monopole antenna with complementary split ring resonators

Triple notch slotted monopole antenna with complementary split ring resonators

Triple notch slotted monopole antenna with complementary split ring resonators

This paper solemnly aims on demonstrating the triple band notched design of ultra-wideband with complementary split ring resonator (CSRR) along with inverted T-shaped stub in the patch. The designe...