Stable Radiation Performance Research Articles

Copper Paste Printed Paper‐Based Dual‐Band Antenna for Wearable Wireless Electronics

AbstractWearable wireless electronics is becoming a significant research area because of the unique features of this technology. Within this field printed antennas are the key electrical component accomplishing the signal transmission and energy harvesting tasks and at the same these antennas need to be lightweight, environmentally friendly, safe to wear, and easy to conform. Currently, the majority of available paper‐based antennas are designed for RFID, sensing, UWB, WLAN, and medical applications, with just a few being utilized in wearable applications, particularly for wireless body area network (WBAN). Furthermore, few studies have been conducted on the usage of printable copper conductive materials and low‐temperature plasma technique for the fabrication of such antennas. This study demonstrates the realization of a dual‐band paper‐based wearable antenna by screen‐printing of a plasma‐sintered conductive copper paste. The copper paste, composed of 51 wt% solid particles, can easily produce desired conductive patterns on photo paper after printing and a subsequent plasma sintering, with a good adhesion. The antenna designed on photopaper operates in the frequency bands of 1.73–2.55 GHz and 7.66–8.89 GHz. Free‐space simulation and measurement results reveal that the antenna exhibits stable radiation performance in the targeted WBAN (2.4–2.4835 GHz) and X uplink (7.9–8.4 GHz) frequency bands, together with low profile, excellent conformality and acceptable SAR values on the body and no electronic waste formed after disposal, making it a competitive candidate for usage in wearable wireless electronics.

Dual-Polarized Heterogeneous Stacked Patch Antenna With Stable Radiation Performance and High Efficiency

Dual-Polarized Heterogeneous Stacked Patch Antenna With Stable Radiation Performance and High Efficiency

Wideband nonuniform metasurface antenna with stable gain

Abstract A novel wideband nonuniform metasurface antenna with stable gain is demonstrated. The nonuniform metasurface is composed of square patches and rings and is excited by a slot antenna. Based on characteristic mode analysis, two characteristic modes with same current direction are selected to achieve stable radiation performance in a wide frequency range. The wideband operation is achieved by assembling the resonant modes of the metasurface and slot antenna. The measured results show that the −10 dB impedance bandwidth of the proposed antenna is from 4.3 to 8.4 GHz (64.57%), and the 2 dB gain bandwidth is from 4.3 to 6.2 GHz (36.2%) with a peak gain value of 9.42 dBi. Moreover, broadside radiation performance is achieved.

A broadband mono‐cone antenna employing a shorted parasitic ring and parasitic metal pillars

AbstractThis letter proposes a broadband mono‐cone antenna with a shorted parasitic ring and parasitic metal pillars. Four parasitic metal pillars expand the high‐frequency operation band, while a shorted parasitic ring increases the current flow path and expands the low‐frequency operation band. A 148.3% impedance bandwidth for VSWR ≤ 2 from 0.831 to 5.6 GHz is attained. The antenna has stable radiation performance across the entire operation spectrum. The simulated and measured results show a good agreement. It is exceptionally compatible with GSM900, DCS1800, PCS1900, UMTS, IMT2000, WiBro, WiMAX2350/3500, LPWAN, wireless LAN (IEEE 802.11b), and a portion of the WLAN/Wi‐Fi frequency spectrum. Indoor applications such as wireless energy collection, partial discharge detection, and so on are possible for the proposed antenna.

Ultra-low SLL slotted waveguide antenna array using Chebyshev aperture distribution function for MM-wave tracking radar applications

A non-uniform aperture distribution slotted waveguide antenna is presented. The slotted waveguide antenna array is chosen for its ease for aperture distribution control and the flexibility of gain adjustment. Multiple aperture distribution functions, including uniform, binominal, Chebyshev, and Blackman, have been extensively investigated to achieve the best possible side lobe suppression. These distribution functions have been converted to slot displacement from the center line of the antenna. Number of slots in the proposed array is chosen to be eight to satisfy the required gain for mm-wave radar tracking application. The proposed antenna is simulated and optimized using the full wave simulator package (CSTMWS). Rounded edge slots are adapted instead of the sharp ones, as they are more applicable for the CNC fabrication process. An eight-slot waveguide antenna is fabricated and gold-plated, considering the Chebyshev distribution approach. The proposed design achieves very stable radiation characteristics and performance over the operating bandwidth, which extends from 33.6 GHz up to 35.9 GHz. At 35 GHz, the total realized gain of the overall antenna is found to be 13.4 dBi, with an overall radiation efficiency of 95.21 %. An obvious low SLL of −30 dB is obtained at the frequency of 35 GHz. The low side lobe level parameter is very crucial for radar applications as it enhances the overall target SNR and reduces false target observations. The pre-stated antenna characteristics make it a good candidate for mm-wave radar applications and point-to-point communications (P2P).

Broadband dual-polarized antenna array with enhanced radiation pattern stability

ABSTRACTIn this paper, a broadband dual-polarized antenna array with stable radiation pattern is proposed for 5 G base station applications. The proposed antenna array consists of a 2 × 2planarantennaarray, four 2 × 2 circle patch parasitic structures and a metal reflector. Based on the principal of the FP (Fabry-Perot) antenna to achieve the stable radiation pattern, when the parasitic loading height meets the resonant height of the FP antenna, serious radiation pattern distortion in large reflector environment could be improved effectively. A prototype of the 2 × 2 broadband dual-polarized antenna array is designed and fabricated. The measured results show that the −10 dB bandwidth of the proposed broadband dual-polarized array is able to cover 3.23–5.06 GHz with high isolation which is greater than 25 dB over the entire operating band. The antenna elementsofthearrayarecapableofmaintainingstable radiation pattern throughout the operating frequency range. The HPBW (half-power beam-width) in the horizontal plane is effectively controlled at 67°±5°with a gain of 8.8 ± 0.5 dBi. Due to the stable radiation performance mentioned above, the proposed dual-polarized array can be applied to future 5 G and sub-6 G base station applications.

Miniaturized Broadband Dual-Polarized MIMO Antenna Array With Stable Radiation Pattern for Base-Station Application

A wideband dual-polarized MIMO antenna array having small size and stable radiation performance for base station applications is introduced. The antenna element, which is formed by four folded dipole antennas arranged in a small square aperture, is introduced to obtain excellent impedance matching and steady radiation pattern within a broad bandwidth of 36.7% (0.69-1 GHz) with low profile. Based on the high-performance element, a compact broadband dual-polarized MIMO array for mobile communications is then designed. To stabilize the radiation pattern of the MIMO array, a new method of element-shared scheme and 90° phase compensation are introduced to design the MIMO array to obtain stable half power beamwidth (HPBW) of around 64° for desired 120° sector coverage of cellular mobile communications. A special feed network with good performance is designed to excite the MIMO array. The MIMO array introduces a broad bandwidth of 43.7% (0.68-1.06 GHz) for reflection coefficient < -15 dB, as well as good isolation of more than 25 dB between all the ports. Steady radiation pattern with HPBW of 64±7° as well as low sidelobe level of below -15 dB are observed, which is desirable for modern mobile communications.

High-Efficiency Air-Filled Wideband ±45° Dual-Polarized Slot Array Antenna

This communication presents a wideband ±45° dual-polarized slot array antenna based on full metal structure. Two sets of ±45°-tilted radiating slots are in staggered arrangement, which shifts the polarization plane to the low sidelobe plane. This achieves low sidelobe levels (SLLs) in E- and H-planes for both polarizations. The radiating slots in a row for each polarization are further combined, forming a long slot to obtain stable radiation performance over a wide frequency range. Two compact full-corporate feeding networks based on the double-ridge waveguide (DRW) and the square coaxial line (SCL) are employed to excite the radiating slots of respective polarizations. A prototype of ±45° dual-polarized 8×8 slot array operating at Ku-band is implemented for demonstration. Experimental results show that the antenna is free from grating lobes and exhibits stable, consistent radiation patterns for the two polarizations over the frequency range of 11-15 GHz. Moreover, the SLLs are less than -25.2 dB and the antenna efficiency is over 79.4% across the same frequency band.

140-GHz Wideband Array Antenna-in-Package Using Multimode Resonance

A 140-GHz wideband array antenna-in-package (AiP) that uses multimode resonance is proposed based on a low-profile multilayer printed circuit board (PCB), which can be incorporated with flip-chip technology and an integrated transceiver. Using the multiple resonances of a patch and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /4 monopole-type feeder, a simulated impedance bandwidth of 53% and stable radiation performance over the operating band were achieved. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $ </tex-math></inline-formula> 4 antenna array achieves a gain of up to 18.1 dBi, a radiation efficiency of 80%, and a cross-polarization discrimination (XPD) of over 20 dB. By combining the elements with a feed network composed of striplines, single and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $ </tex-math></inline-formula> 4 antenna arrays were designed and fabricated. The capacitance caused by the limitations of the fabrication process was analyzed and overcome using a novel capped-cavity structure. From the experiment, a −10 dB impedance bandwidth of 31% was measured.

Wideband Dual Linearly Polarized Hollow- Waveguide Septum Antenna Array for Ku-Band Satellite Communications

This article presents a Ku-band full-corporate-feed dual linearly polarized (LP) hollow-waveguide (HW) septum antenna array. A modified low-profile septum polarizer, worked as the radiating element, is designed to push the radiation nulls out of the desired passband upon odd-mode excitation, which helps to achieve stable and consistent radiation performance for both H-pol and V-pol. Square coaxial lines are employed to realize two sets of full-corporate feeding networks with compact size, enabling close spacing between the two adjacent radiating elements. A magic-T based on the single-ridge waveguide is designed to provide in-phase and out-of-phase responses for the feeding networks so that the dual LPs can be achieved. A prototype covering 10.5–14.5 GHz is designed, fabricated, and measured for demonstration. Experimental results show that more than 17.3 dBi peak gain and better than 79% antenna efficiency for both polarizations are achieved within the desired frequency band. In addition, the antenna is free from grating lobes over the same frequency band.

Broadband dual‐polarized dipole antenna array for 2G/3G/4G/5G base station

AbstractA broadband dual‐polarized antenna array with excellent impedance matching and stable radiation performance is proposed. The array comprises four folded‐dipole antenna elements. Two trapezoidal baluns are used to excite the folded‐dipole antenna to obtain good impedance matching and generate a ±45°‐polarized radiation pattern. To improve the impedance matching and achieve steady radiation performance, a square parasitic director is used and placed above the folded dipoles. The antenna element realizes a broad bandwidth of 76.9% (voltage standing wave ratio [VSWR] &lt; 1.5 from 1.69 to 3.8 GHz) and high isolation of 28 dB. Then an antenna array comprised of four elements is designed. It is fed by two miniaturized 1‐to‐4 power divides. Several metal baffles are added between adjacent elements to reduce the mutual coupling. The array achieves a broad bandwidth of 78.4% (VSWR &lt; 1.5 from 1.66 to 3.8 GHz), high isolation of 25 dB, stable half power beamwidth in the E‐plane within 65° ± 5°, and high gain within 12–15 dBi.

A continuous frequency tuning Fabry–Perot Cavity antenna with stable radiation performance

AbstractThis paper presents a continuous frequency tuning Fabry–Perot Cavity (FPC) antenna of which the operating frequency can be varied from 4.87 to 5.84 GHz (18.1%). The cavity of the proposed antenna is excited by a double-layer antenna structure, which is made up of a main square patch and a parasitic one. The superstrate is a frequency-selective surface, consisting of 6 × 6 square-patch-type unit cells. The frequency tuning property is realized by employing 48 phase-changing elements placed around the main patch, which forms a reconfigurable high impedance surface (HIS). By controlling the biasing voltages of the varactors inserted in the HIS element, its capacitances and reflection phases can be varied continuously, which leads to a variation of the operating frequency. An antenna prototype has been fabricated and measured for validation. The measured results are in good agreement with the simulated ones. In the frequency tuning range, the measured realized gains have a smaller variation from 10.2 to 14.1 dBi compared with other reported frequency tuning FPC antennas.

A broadband stable gain antenna using nonuniform hexagonal-Slot metasurface

ABSTRACT This paper demonstrates a broadband metasurface antenna with stable gain. A 4 × 4 square patches metasurface loaded with nonuniform hexagonal slots is proposed. To achieve stable radiation performance in broadband range, two characteristic modes with the same current direction are selected as operating modes of the metasurface. A slot antenna is employed to excite the metasurface. By combining the resonant modes of metasurface and slot antenna, the broadband is obtained. The measured results show that, the −10 dB impedance bandwidth of the proposed antenna is 4.36–8.21 GHz (61.2%), the 2 dB gain bandwidth is 4.36–7.2 GHz (49.1%), and the peak gain value reaches 10.6 dBi.

A broadband and low‐profile magnetoelectric dipole antenna with low radar cross section

AbstractIn this study, a novel broadband and low profile magnetoelectric dipole (MED) antenna with a low radar cross section (RCS) is proposed. The 10 dB RCS reduction is achieved by shifting the reflected energy to six directions, which is an efficient optimization method based on convolutional operations. Specifically, the polarization conversion metasurface (PCM) unit with high polarization conversion rate is constructed and employed in the MED antenna for RCS reduction. The proposed antenna is fabricated and measured. Measured results depict that the low RCS antenna offers good impedance matching in 12–15.6 GHz (relative bandwidth 26%). Compared with the reference antenna, the RCS of the proposed antenna is reduced by more than 10 dB from 9.9 to 16 GHz. It is proved that the proposed antenna has broadband and stable radiation performance and outstanding specular reflecting suppression capabilities.

A Dual-Polarized Reconfigurable Reflectarray Antenna Based on Dual-Channel Programmable Metasurface

The concept of dual-polarized reconfigurable reflectarray (RRA) featuring dual-polarized beam control is proposed and demonstrated using a dual-channel programmable metasurface. The p-i-n diodes are incorporated into each metasurface element as the active components to provide independent phase control in two orthogonal polarization channels. By altering the working states of each p-i-n diode, well-defined beam scanning can be obtained. Element design, focal diameter ratio selection, and discretized phase distributions are carefully optimized to ensure stable radiation performance of the proposed RRA. As verification, a prototype consisting of 20 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times20$ </tex-math></inline-formula> elements is fabricated and measured, which is controlled by a field programmable gate array-based controller. Measured results show that wide-angle beam scanning up to ±40° can be obtained around 7.45 GHz, with peak gains of 21.13 and 20.89 dBi in dual channels, corresponding to aperture efficiencies of 16.35% and 15.47%. The proposed dual-polarized RRA brings a new freedom in polarization manipulations for versatile beam scanning, which provides promising applications in wireless communication and tracking/detecting systems.

Wide-Angle Impedance Matching Layer-Enhanced Dual-Polarization sub-6 GHz Wide-Scan Array for Next-Generation Base Stations

A new sub-6 GHz antenna array that supports slant ±45° dual-polarization multiple-input multiple-output (MIMO) communications with high interport isolation and stable radiation performance over wide scan angles and bandwidths is designed. An architecturally inexpensive solution, which combines a standard truncated waveguide array and a single-layer patterned metasurface superstrate with wave manipulation capabilities, is proposed. A task-oriented formulation is adopted to mathematically formulate the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">EM</i> associated multiscale design problem, then solved with an innovative instance of the system-by-design (SbD) paradigm where the fast and reliable modeling of the device is yielded by an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ad hoc</i> artificial intelligence-based surrogate. The final layout of the antenna array is validated with industry-standard full-wave numerical simulators.

Dual-Band Aperture Shared Antenna Array With Decreased Radiation Pattern Distortion

In this communication, a dual-band aperture-shared antenna array (ASAA) is developed for base station. This ASAA contains a 4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 4 high-band (HB) antenna array, which operates from 3.4 to 3.8 GHz, and low-band (LB) antenna, which operates from 0.69 to 0.96 GHz. For decreasing pattern distortion of HB array due to the induced current in the LB element, a method following two side chokes (TSC) is proposed. By loading the TSC, the LB element exhibits a cross-band scattering suppression performance in HB. Furthermore, ASAA is fabricated and measured. Measured results show that the proposed ASAA exhibits stable radiation performance in both LB and HB. Also, the LB antenna can cover 0.69–0.96 GHz (VSWR < 1.5). Hence, the antenna array can be a good candidate for future 5G and 2G/3G/4G aperture-shared base station antenna array.

Analysis Of Novel Curve Microstripline Array Antenna Design In X Band Frequency For Satellite Communication

The design of a novel curve microstripline 2x2 array antenna is presented in this research. In this design, antenna work in X Band frequency. The total size of antenna is 40mm x 40mm. The result indicates that the antenna characteristics parametric showed by Voltage Standing Wave Ratio (VSWR≤2) of the proposed antenna is 1.06 (in simulated); 1.29 (in measured) and 1.20 (in numeric analyzed), bandwidth is 260.0 MHz (in simulated) and 310.0 MHz (in measured) and reflection coefficient is 0.03 (in simulated) and 0.17 (in measured) and return loss is -29.43dB (in simulated) and -27.12dB (in measured) respectively. The antenna has achieved a stable radiation performance with a maximum gain of 6.67dB (in simulated) and 5.53dB (in mesured). Novel curve microstripline 2x2 array antenna with 50 Ohm impedance and easy integration are making this model suitable for X-Band frequency (8GHz-12GHz) satellite communication applications. Details of the proposed antenna design and results are presented and discussed.

Analysis Of Novel Curve Microstripline Array Antenna Design In X Band Frequency For Satellite Communication

The design of a novel curve microstripline 2x2 array antenna is presented in this research. In this design, antenna work in X Band frequency. The total size of antenna is 40mm x 40mm. The result indicates that the antenna characteristics parametric showed by Voltage Standing Wave Ratio (VSWR≤2) of the proposed antenna is 1.06 (in simulated); 1.29 (in measured) and 1.20 (in numeric analyzed), bandwidth is 260.0 MHz (in simulated) and 310.0 MHz (in measured) and reflection coefficient is 0.03 (in simulated) and 0.17 (in measured) and return loss is -29.43dB (in simulated) and -27.12dB (in measured) respectively. The antenna has achieved a stable radiation performance with a maximum gain of 6.67dB (in simulated) and 5.53dB (in mesured). Novel curve microstripline 2x2 array antenna with 50 Ohm impedance and easy integration are making this model suitable for X-Band frequency (8GHz-12GHz) satellite communication applications. Details of the proposed antenna design and results are presented and discussed.

Cross-Shaped Interconnected Receiver–Transmitter Metasurface for a Circularly Polarized Fabry–Pérot Antenna

In this paper, we proposed a cross-shaped interconnected receiver–transmitter (RT) metasurface (MS) that was employed for a high-aperture-efficiency, high-gain, circularly polarized Fabry–Pérot (FP) antenna. The RT-MS unit cell consists of upper-layer cross-shaped patch and lower-layer squared patch that are connected by two metal-probes that cross the sandwiched middle metal-plane. The bottom patch receives electromagnetic wave, functioning as receiver, and transfers it to the top cross-shaped patch passing through the two mental probes. Through tuning the relative locations of the two probes, equal amplitude and 90° phase difference can be obtained, thereby achieving linear to circular polarization conversion performance, indicating that the MS has the ability of tuning transmission coefficients independently. Meanwhile, the MS is designed to present high reflectivity that high-gain property is obtained when forming a FP cavity. Then, an off-center coaxial patch antenna is applied as feeder due to its stable radiation performance. To further enhance the performance of the source antenna, an AMC structure is adopted to improving the radiation gain, efficiency and radiation directivity by suppressing surface wave loss. Meanwhile, the profile was also reduced. The linearly polarized wave emitting from the feeder multi-reflected in the FP cavity formed by MS superstrate and AMC structure, and then transmit it in phase to the space, thus a high-gain and CP radiation is achieved as final. The measurements demonstrate that the proposed RT-MS-based antenna perform a maximum gain of 18.7dBic at 9.4GHz with aperture efficiency of 76.7%, and a circular polarization bandwidth within 9.2-9.7GHz, while, the antenna owns a compact size of only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.85\lambda _{0}\times 2.85\lambda _{0}$ </tex-math></inline-formula> . Thus, a novel RT-MS-based FP antenna exhibit a good radiation performance that can be a candidate in applying to communication and point-to-point links.