H-plane Radiation Patterns Research Articles

Dual-band GPS/LoRa antenna for internet of thing applications

This paper presents the design and characterization of a compact dual-band microstrip antenna for GPS and long range (LoRa) internet of thing (IoT) applications. The antenna operates at 868 MHz and 1.57 GHz and has a gain of 3.35 dBi and 5.08 dBi, respectively. The antenna design is optimized using CST microwave studio software (MWS®), and both simulation and measurement results are in close agreement. The antenna features a directional E-plane and omnidirectional H-plane radiation pattern in each band of operation. The proposed antenna’s compact size and dual-band capability make it suitable for IoT applications that require GPS and LoRa communication in a small form factor. The results presented in this paper demonstrate the feasibility and effectiveness of the proposed antenna design.

A Novel Bow-Tie Balun-Fed Dual-Polarized Crossed Dipole Antenna

A broadband dual-polarized crossed dipole antenna is proposed in this paper. To achieve a wide impedance bandwidth and low-profile configuration, a novel bow-tie balun is applied to this antenna. Firstly, the working mechanisms of both bow-tie baluns and the antenna are introduced. Then, the parametric study and design guidelines are presented. Finally, the optimized antenna is fabricated, measured, and analyzed. The simulated and measured results show that the antenna has a wide impedance bandwidth from 2.42 GHz to 6.48 GHz. The fractional bandwidth is 91.2%. Moreover, within the whole band, the E-plane and H-plane radiation patterns are stable. The port isolation is greater than 20 dB, and the cross-polarization discrimination ratio is better than 25 dB. The proposed antenna achieves a realized gain of 7.5 dBi ± 0.5 dBi. It can be a good candidate for sub-6 GHz wireless communications or short-range radar applications.

Triple-Band Reconfigurable Monopole Antenna for Long-Range IoT Applications

In this study, a novel reconfigurable triple-band monopole antenna for LoRa IoT applications is fabricated on an FR-4 substrate. The proposed antenna is designed to function at three distinct LoRa frequency bands: 433 MHz, 868 MHz, and 915 MHz covering the LoRa bands in Europe, America, and Asia. The antenna is reconfigurable by using a PIN diode switching mechanism, which allows for the selection of the desired operating frequency band based on the state of the diodes. The antenna is designed using CST MWS® software 2019 and optimized for maximum gain, good radiation pattern and efficiency. The antenna with a total dimension of 80 mm × 50 mm × 0.6 mm (0.12λ0×0.07λ0 × 0.001λ0 at 433 MHz) has a gain of 2 dBi, 1.9 dBi, and 1.9 dBi at 433 MHz, 868 MHz, and 915 MHz, respectively, with an omnidirectional H-plane radiation pattern and a radiation efficiency above 90% across the three frequency bands. The fabrication and measurement of the antenna have been carried out, and the results of simulation and measurements are compared. The agreement among the simulation and measurement results confirms the design’s accuracy and the antenna’s suitability for LoRa IoT applications, particularly in providing a compact, flexible, and energy efficient communication solution for different LoRa frequency bands.

Investigations of physicochemical and microwave absorption performance of NiCo2S4/AgBr nanocomposite in X-band frequency

The advantages of the microwave materials' low weight and exceptional absorbing power are crucial for addressing the EM problems in stealth technology. The structure and absorber thickness optimization is suggested by the current work. Herein, we increased the absorption properties of the NiCo2S4/AgBr (NCAG) nanocomposite by modifying the filler loading in the composite matrix. XRD, VSM, Raman, and FESEM were employed to find the structural and morphological properties of the NCAG composites. At 9.7 GHz, the thinnest layer of 1.4 mm was reported to have a -24 dB minimum reflection loss. The improved absorption bandwidth, however, is 3.8 GHz. The H-plane radiation patterns of an NCAG sample with a 25 wt.% filler loading were determined using the free-space approach (thickness of 1.4 mm). The RL resonance peaks at 10.9 GHz and 11.4 GHz demonstrate the 25 wt% and 35 wt% samples' strong high-frequency absorption responses. The key factors in the improvement of the reflection loss and absorption efficiency were excellent conductive response, better matching properties, and electromagnetic losses.

Broadband Cross-Slotted Patch Antenna for 5G Millimeter-Wave Applications Based on Characteristic Mode Analysis

This article proposes a wideband differentially fed dual-polarized magnetoelectric (ME) dipole for millimeter-wave (mm-Wave) applications. Various electric and magnetic characteristic modes of a slotted patch antenna are investigated and utilized effectively to create a stable broadside radiation pattern, covering fifth-generation (5G) frequency bands from 24.25 to 40 GHz. To implement this, the lifted ground (LGND) concept is applied to achieve a 57.1% impedance bandwidth for a single antenna element. In addition, the three resonances of the antenna can be manipulated independently. The use of differential feeding allows more than 36 dB of port-to-port isolation across the entire operating band. The measured gains of the single element and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> 2 array are 8.4 and 13.4 dBi, respectively. Also, the measured results indicate symmetrical E- and H-plane radiation patterns and cross-polarization levels lower than −26 dB. With the favorable electrical performance, compact size, simple structure, and low-cost fabrication, the proposed ME dipole is a promising candidate for mm-Wave Antenna-in-Package (AiP) applications.

Low-profile bandwidth and E-plane radiation pattern reconfigurable patch antenna for sub-6 GHz 5G applications

In this work, a low-profile bandwidth and E-plane radiation pattern reconfigurable microstrip antenna is presented for the fifth generation (5G) sub-6 GHz, 3.3 to 4.2 GHz band. The proposed antenna is miniaturized using a partial ground plane technique. The bandwidth and the pattern reconfigurability are realized using a reconfigurable second element feed line and an additional λ/8 connecting stub of a 2-element circular patch array. The additional λ/8 connecting stub transforms a conventional series RLC into a parallel RLC combination leading to larger bandwidth. The working principle and the design process of each iteration have been detailed. The working principle is validated using the surface current distributions in different modes and developing and testing a prototype. The proposed antenna structure has two operating modes covering from 3.28 to 4.34 GHz band; (I) measured 19.4% fractional bandwidth, unidirectional E-plane pattern and (II) 27.4% fractional bandwidth, bidirectional E-plane pattern. The measured centre frequency of both operating modes is 3.5 GHz, and 3.79 GHz with continuous coverage of the 5G band. The measured H-plane radiation pattern of the antenna is identical in both operating modes.

Design of a novel compound decoupling structure for multiple‐input multiple‐output antenna array

A novel compound structure made up of Y-shaped microstrip interdigital lines, slots etched into the ground plane and metallized vias embedded in the substrate is designed to enhance the isolation between H-plane antenna array elements in this paper. Also, the operating mechanism of the decoupling structure is detailedly analyzed, as it can transform the coupling mode and suppress the transmission of surface current from one port to another. Then, after inserting the structure into the coupled antenna array, whose edge-to-edge distance between antenna elements is only 4 mm (0.07λ0), a 32.2 dB reduction of mutual coupling at the operating frequency 5.25 GHz is obtained. Moreover, the H-plane radiation pattern is modified, the radiation gain is increased, and the diversity performance is improved. Simulated results are in good accordance with measured results, verifying decoupling effectiveness of the proposed structure. The proposed structure has high feasibility in the utilization of MIMO or the wireless Rx/Tx system.

Novel Compact Design and Investigation of a Super Wideband Millimeter Wave Antenna for Body-Centric Communications

This paper presents a novel design for a multiple band millimeter wave antenna with a wide active region in the extremely high frequency (EHF) range. The antenna's performance was tested at three evenly separated frequencies: 60 GHz within the V-band region, 80 GHz within the E-band region, and 100 GHz. Simulation exhibits satisfactory results in terms of gain and efficiency, although the efficiency falling tendency for higher frequency persists. As millimeter wave antennas have miniature-like dimensions and low penetration depth into human body layers, the performance of these antennas is less disturbed by the presence of a human body, making them ideal for body-centric wireless communication (BCWC) applications. Thus, a human body model was created virtually with the necessary property data. Simulations are repeated at the same frequencies as before, with the antenna kept close to the constructed human body model. The results were promising as the gains found increased radiation patterns and return loss curves remained almost identical, except some efficiencies that were considered. Some H-plane radiation patterns are changed by the presence of a human body. Although all three frequencies present satisfactory results, 60 GHz is found to be more balanced, but 100 GHz shows better gain and directivity. Multiple band operability makes this antenna suitable for various applications. Finally, a distance-based analysis was conducted to realize the in-depth characteristics of the antenna by placing the antenna at five different gaps from the human body. The result verifies the antenna’s category as suitable for body-centric communications.

Double Meander Dipole Antenna Array with Enhanced Bandwidth and Gain

In this paper, a new design of high gain and wide bandwidth microstrip patch antenna array containing double meander dipole structure is proposed. Two in-phase resonant frequencies in the Ku-band (12–18 GHz) could be achieved in the double meander dipole array structure, which lead to enhance impedance bandwidth without costing extra design section. Besides, further enhanced gain of 2 dBi of the array over the entire operating frequency range has been achieved by introducing a double-layer substrate technique. The proposed antenna has been fabricated using the E33 model LPKF prototyping PCB machine. The measurement results have been performed, and they are in very good agreement with the simulation results. The measured –10 dB impedance bandwidth indicates that the array provides a very wide bandwidth which is around 30% at the center frequency of 15.5 GHz. A stable gain with a peak value of 10 dBi is achieved over the operating frequency range. The E- and H-plane radiation patterns are simulated, and a very low sidelobe level is predicted. The proposed antenna is simple and has relatively low-profile, and it could be a good candidate for millimeter wave communications.

A Broadband and Wide-Beamwidth Dual-Polarized Orthogonal Dipole Antenna for 4G/5G Communication

A broadband and wide-beamwidth dual-polarized orthogonal dipole antenna for 4G/5G communication is presented in this letter. A pair of orthogonal deformed fan-shaped dipoles was used to obtain dual-polarization. The parasitic elements and metal cavity structure were used to increase the impedance bandwidth effectively. And the half-power beamwidths (HPBWs) of the antenna were effectively widened by using the metal cavity. Furthermore, a 1 × 4 antenna array was designed. The measured HPBWs of E-plane and H-plane radiation patterns were greater than 90° in the operating frequency band of 1.7-3.22 GHz (voltage standing wave ratio (VSWR) <; 2.0), and the gain was greater than 0 dBi in the range of ±60° pitch angle. The isolation of the two input ports was higher than 29 dB in the band of 1.7-3.22 GHz (61.8%).

A foldedhigher‐modeslot antenna with enhanced bandwidth and radiation pattern reshaping

In this article, an approach to reshape the radiation pattern of the 1.5λ-mode of the slot antenna is proposed. Unlike previous works on slot antenna operating at the fundamental mode with a broadside radiation performance, the proposed slot antenna holds four symmetric radiation beams by resonating at its radiative λ- and 1.5λ-mode. Initially, by folding the straight slot radiator at one short-ended terminal, radiation patterns in H-plane of the 1.5λ-mode could be significantly reshaped from the broadside beam into four symmetric radiation beams, while that of the λ-mode almost remains unchanged. Then, a pair of slot stubs is symmetrically introduced to further improve the bandwidth of multibeam radiation performance. An antenna prototype is finally fabricated and measured to validate the predicted performance. Good agreement between the simulated and measured results is observed. The antenna operates in a frequency range of 3.64 to 3.96 GHz with S11 lower than − 10 dB under dual-mode resonance. And four symmetric beams for radiation have been successfully obtained at the directions of 40°, − 40°, 140°, and − 140° with respect to the broadside direction across the whole operating bandwidth.

Synthesis approach to design a compact printed monopole filtenna for 2.4 GHz Wi‐Fi application

This communication presents a compact low cost filtenna (35 mm × 30 mm) operating in 2.31 to 2.49 GHz spectrum for possible applications pertaining to 2.4 GHz Wi-Fi standards 802.11b, 802.11g, and 802.11n. Initially, two microstrip square open loop resonators are designed to serve as band-pass filters with resonant frequency of 2.4 GHz. Adapting the synthesis approach, the second resonator is replaced by inverted L-shaped monopole antenna designed at 2.4 GHz. The antenna is integrated to filter through coupled line admittance inverter to form a compact module with near zero insertion loss within the proposed operating frequency band, filtenna possess uniform omnidirectional radiation pattern in H-plane and monopole pattern in E-plane, steep skirt at both edges, 7.5% fractional bandwidth, good return loss and low cross polarization characteristics. The simulated design is validated by measurements of parameters of prototype fabricated on FR4 substrate, slight acceptable discrepancy is experienced which can be attributed to fabrication tolerances and variation in material characteristics.

Design of Efficient 37 GHz Millimeter Wave Microstrip Patch Antenna for 5G Mobile Application

Millimeter wave (mmWave) wireless technology has become a part of human life for high-speed and secure data transmission. This paper presents a square-slotted microstrip patch antenna at 37 GHz resonant frequency for mmWave wireless communication. The antenna consists of one H-slot and one inverted T-slot loaded over the radiating patch. The proposed antenna has been designed and investigated on Rogers RT5880 substrate with relative permittivity 2.2 and loss tangent 0.0009 using Electromagnetic Simulation Software CST Microwave Studio. The result of this paper shows minimal return loss −43.05 dB, gain 8.18 dB, and impedance bandwidth 16.22% at 37 GHz resonant frequency. The voltage standing wave ratio (VSWR), E-plane, and H-plane radiation pattern has also presented for the proposed antenna which can be strong candidate for 5G mmWave cellular communication.

A compact printed ultra-wideband filtenna with low dispersion for WiMAX and WLAN interference cancellation

A printed monopole filtenna fed by a co-planar waveguide with U-shaped split slot on patch and circular split ring resonator pairs at the other side of feed is proposed in this letter. The compact filtenna of dimension 0.32λ × 0.215λ (λ denotes wavelength corresponding to 2.68 GHz) is capable of providing large bandwidth from 2.68 to 8.72 GHz with dual frequency notch bands over 3.28–3.84 and 4.95–6.02 GHz, primarily to eliminate the WiMAX and WLAN interferences. The dual notched antenna performances are evaluated by simulation and experimental measurement and compared to those of recently reported ultra-wideband (UWB) notched antennas. The proposed filtenna provides bidirectional E-plane and omni-directional H-plane radiation patterns with gain variation of 2–4.5 dBi and average radiation efficiency of 78% in its pass band. Also the filtenna offers minimal dispersion characteristic as stable group delay response, and linear variation of transfer function (S21) is achieved in its pass bandwidth.

Wideband, Low-Profile Slot-Fed Dipole-Patch Antenna and Array

A wideband, low-profile dipole-patch antenna element consisting of a printed dipole and four tightly coupled microstrip patches is proposed. The element, housed in a substrate-integrated-waveguide (SIW) cavity, is slot-fed by two vias residing on the opposite sides of a dumbbell-shaped aperture. The simulated results reveal that it operates from 22.3 to 32.1 GHz for standing-wave ratio (SWR) ≤ 2 with a peak gain of 9.6 dBi, low cross-polarization level less than −25 dB, and stable radiation patterns across the operating band. The element thickness is only 0.071 λ 0, where λ 0 is free-space wavelength at the center frequency of 27.2 GHz. An SIW-fed 8 × 8 antenna array with nonuniform power distribution is then designed, fabricated, and measured to verify the properties of the element. The measured E- and H-plane radiation patterns are stable across the operating band with sidelobe and cross-polarization levels below −17 and −22 dB, respectively.

Design and implementation of miniaturized wideband microstrip patch antenna for high-speed terahertz applications

In the twenty-first century, graphene is widely used in wireless communication, especially in terahertz applications because of its amazing electrical, mechanical, and optical properties. This paper presents a graphene-based microstrip patch antenna at 0.72 THz resonant frequency for wireless communication. The proposed antenna shows 37.50% impedance bandwidth ranging from 0.53 to 0.84 THz at the center frequency of 0.72 THz. The result is demonstrated in terms of return loss (s11 < − 10 dB), voltage standing wave ratio (VSWR), input impedance, E-plane, and H-plane radiation pattern. The designing and simulation are performed using a full-wave electromagnetic simulator CST microwave studio based on the finite difference time domain method. The simulation output shows a minimal return loss − 59.97 dB, VSWR 1.007, and good radiation pattern at 0.72 THz resonant frequency, which would be an excellent candidate for future wireless communication as well as medical imaging, homeland defense system, explosive detection, and material characterization application.

A dual-port microstrip rectenna for wireless energy harvest at LTE band

To wirelessly harvest RF energy at LTE band, a novel compact and efficient dual-port microstrip rectenna is proposed. An antenna designed with two ports and featured by arrow-shaped, circular and rectangular slots is presented. A broadband rectifier including a voltage doubler rectifying circuit and a novel matching network is developed to convert the RF power captured by the antenna into DC power. For well matching between the antenna and the rectifying circuit, the matching network which consists of double 70-deg fan-shaped stubs, no-uniform transmission line and double 55-deg fan-shaped stubs is designed. The prototypes of the proposed antenna and rectifier are respectively fabricated. The simulation and experimental results show that the antenna is able to harvest energy from different frequencies when fed by separate microstrip feeding line. The distribution of current density along with the radiation pattern in E-plane and H-plane is investigated. Besides, the conversion efficiency and output voltage of the rectifier are studied. To test the performance of the proposed rectenna, an indoor measurement is conducted. The results demonstrate that the RF-to-DC conversion efficiency of the proposed antenna is around 42% and the output voltage is around 0.9 V, indicating its potential application in the RF energy harvest.

Low‐profile microstrip patch antenna with simultaneous enhanced bandwidth, beamwidth, and cross‐polarisation under dual resonance

A low-profile microstrip patch antenna (MPA) with wide bandwidth, wide beamwidth, and reduced cross-polarisation is proposed here. Firstly, the far-zone radiated fields of the MPA are deeply studied to improve its radiation performance. It demonstrates that the E -plane half-power beamwidth (HPBW) of the antenna could be progressively widened by using a single equivalent slot instead of two equivalent slots. Meanwhile, its high cross-polarisation of the H -plane radiation patterns could be successfully decreased down by enlarging the width of the rectangular patch and loading the shorting pins. Secondly, the input impedance of the MPA operating in the fundamental mode is extensively investigated. The results illustrate that the resonant frequencies of its dual modes could be reallocated in proximity to each other for bandwidth enhancement by properly selecting the dimension of radiating patches. Finally, the proposed antenna is fabricated and tested. Experimental results show that the antenna has gained an improved bandwidth (| S 11 |<;-10 dB) of about 12% ranging from 2.70 to 3.03 GHz, while keeping a thin thickness of about 0.029 free-space wavelength. Besides, its H -plane cross-polarisation is kept below -20 dB. Most importantly, the E -plane HPBW of the antenna is extended to around 140° over the wide band.

DESIGN AND DEVELOPMENT OF COMB-SHAPED ME DIPOLE ANTENNA

This paper presents a novel comb-shaped electric dipole and a quarter-wave shorted magnetic dipole in the magneto-electric (ME) dipole antenna. This antenna has been excited by cascaded 1 shaped feed line to exhibit broadside radiation pattern. A wide impedance bandwidth of 24%, with 8.1 dBi peak gain has been achieved for the frequency range 2.2 GHz-2.8 GHz. The antenna also exhibits low side lobe radiations and almost identical E-plane and H-plane radiation patterns in the given frequency range. The 3-dB E-plane and H-plane beamwidth of 101.4° at 2.5 GHz has also been reported. The antenna has a wide potential for various applications in the S band.

Modular Design for a Stacked SIW Antenna Array at Ka-Band

This article presents a modular substrate-integrated waveguide (SIW) antenna array based on H-plane aperture structures for Ka-band. The unitary antenna is based on a SIW aperture antenna with an improved H-plane radiation pattern by means of the implementation of metallic vias in the wave propagation along the H-plane antenna. The inner metallic vias are introduced to form four different sub-apertures at the end of the H-plane aperture antenna, dividing the field from the feeding into four in-phase wavefronts. In that manner, a flatter wavefront is generated to achieve high directivity. Additionally, some periodic parallel strips are printed at the end of the antenna aperture to improve the impedance matching with the air. The H-plane antenna is used as the constituting element for an E-plane array antenna, using four H-plane elements. The E-plane array antenna increases the antenna directivity, providing a pencil-shape beam, based on a series coaxial feeding structure. This feeding strategy favours the antenna modularity at the expense of suffering from a slight beam steering with frequency in the working bandwidth. The proposed antenna has an impedance matching below -10 dB from 32.9 to 37.0 GHz (equivalent to 11.73% bandwidth) with a nearly stable gain of almost 10 dBi for the H-plane unitary element and 14 dBi for the E-plane array. Prototypes of both antennas are manufactured to validate the proposed unitary antenna and array designs.