Showing papers on "Microstrip antenna published in 2018"
TL;DR: In this paper, a filtering antenna based on the filtering-radiating patch (FRP) is proposed, where two radiation nulls are realized at both band edges of the antenna efficiency curve, leading to a sharp band skirt and good selectivity in the boresight gain response.
Abstract: This communication demonstrates a method to design filtering antennas by using the filtering-radiating patch (FRP). The so-called FRP is a structure of a rectangular patch etched with slots. It inherits the radiation performance of conventional patch antennas, and more importantly, introduces filtering feature with a radiation null at either the upper or lower band edge of radiation efficiency curve. The frequencies of radiation nulls are easy to control. Based on the FRP, a novel filtering antenna is proposed. Two radiation nulls are realized at both band edges of the antenna efficiency curve, leading to a sharp band skirt and good selectivity in the boresight gain response. The locations of the two radiation nulls can be flexibly controlled by the lengths of slots. A prototype is fabricated and tested. The measured results show an impedance matching bandwidth of 7% with a center frequency of 5.24 GHz, two radiation nulls at 4.7 and 5.85 GHz, respectively, a realized gain of 6.6 dBi, the cross-polarization rejection larger than 23.4 dB, and the front-to-back ratio better than 15 dB. The presented method demonstrates the capability of not only achieving good filtering-radiating performances but also possessing very simple structures by only etching slots on the patch of a conventional microstrip antenna.
177 citations
TL;DR: In this article, a flexible ultrawideband (UWB) antenna is presented for wearable applications in the 3.7-10.3 GHz band, which is highly tolerant to human body loading and physical deformation.
Abstract: A new flexible ultrawideband (UWB) antenna is presented for wearable applications in the 3.7–10.3 GHz band, which is highly tolerant to human body loading and physical deformation. The antenna exhibits a footprint of 80 mm $\times$ 67 mm and is based on a simple microstrip structure with two modified arc-shaped patches as the main radiator. A full ground plane is maintained on the opposite side of the substrate to suppress antenna loading from the underlying biological tissues and back radiation directed toward the human body. For enhanced flexibility and robustness, the proposed antenna is realized using conductive fabric embedded into polydimethylsiloxane polymer. Promising simulation and experimental results are presented for free-space and in-vitro wearable scenarios. To our knowledge, this is the first UWB antenna with a full ground plane that is concurrently highly tolerant to harsh operating conditions, such as those encountered in wearable applications.
119 citations
TL;DR: In this article, a lower boundary on the achievable radiation quality factor (Q factor) and consequently on the maximum achievable impedance bandwidth has been established for antenna miniaturization, and many new investigations have been conducted to reduce the form factor of different types of antennas while trying to maintain acceptable matching properties and operating bandwidth.
Abstract: Antenna miniaturization has been the subject of numerous studies for almost 70 years [1]-[4]. Early studies showed that a decrease in the size of an antenna results in a direct reduction in its bandwidth and efficiency (hr) [1], [2]. The size limitation translates into a lower boundary on the achievable radiation quality factor (Q factor) and consequently on the maximum achievable impedance bandwidth. Recently, many new investigations have been conducted to reduce the form factor (or the overall size) of different types of antennas while trying to maintain acceptable matching properties and operating bandwidth. These miniaturization techniques are generally related to changing the electrical and physical properties of an antenna.
95 citations
TL;DR: A suspended meta-surface composed periodic square split ring resonators (SRRs) is placed above the antenna array for decoupling and the total efficiency and peak gain of each element, the envelope correlation coefficient (ECC) between the two elements are improved by considerable amounts.
Abstract: In this paper, a method to reduce the inevitable mutual coupling between antennas in an extremely closely spaced two-element MIMO antenna array is proposed. A suspended meta-surface composed periodic square split ring resonators (SRRs) is placed above the antenna array for decoupling. The meta-surface is equivalent to a negative permeability medium, along which wave propagation is rejected. By properly designing the rejection frequency band of the SRR unit, the mutual coupling between the antenna elements in the MIMO antenna system can be significantly reduced. Two prototypes of microstrip antenna arrays at 5.8 GHz band with and without the metasurface have been fabricated and measured. The matching bandwidths of antennas with reflection coefficient smaller than −15 dB for the arrays without and with the metasurface are 360 MHz and 900 MHz respectively. Using the meta-surface, the isolation between elements is increased from around 8 dB to more than 27 dB within the band of interest. Meanwhile, the total efficiency and peak gain of each element, the envelope correlation coefficient (ECC) between the two elements are also improved by considerable amounts. All the results demonstrate that the proposed method is very efficient for enhancing the performance of MIMO antenna arrays.
85 citations
TL;DR: In this paper, a dual-polarized patch antenna element fed by a pair of antisymmetric L-shaped probes is proposed, which is able to introduce feed capacitance to the antenna for broadband operation.
Abstract: A dual-polarized patch antenna element fed by a pair of antisymmetric L-shaped probes is proposed. The designed twin L-shaped probe feeding structure is able to introduce feed capacitance to the antenna for broadband operation. The lengths of the two L-shaped probe feeds are identical, but the feeds are antisymmetric. This feeding design can minimize the unwanted radiation from the probe effectively. The dual-polarized antenna can be operated in the frequency band 1580–2750 MHz, which covers the current mobile communication systems, 3G and 4G and higher band frequencies. A prototype with dual slanted ±45° polarization has been fabricated for validation. Both the simulation and measured results show that the proposed antenna has wide bandwidth of 54% (SWR < 2) with desirable directional radiation patterns in the vertical and horizontal planes, as well as high isolation better than −30 dB between the two input ports.
79 citations
TL;DR: Measured reflection coefficients and radiation patterns demonstrate that the proposed reconfigurable filtering antenna is an eligible candidate for future multifunctional systems incorporating both UWB and WLAN systems.
Abstract: This communication presents a new reconfigurable filtering monopole antenna design with three switchable states for UWB/WLAN applications. The antenna has three independent ports for ultra-wideband state, 2.4 GHz WLAN narrowband state, and 5.8 GHz WLAN narrowband state, respectively. The narrowband state at 2.4 GHz is produced by a first-order microstrip filter using an open-loop resonator, and the narrowband state around 5.8 GHz is obtained by involving a third-order hairpin bandpass filter in the RF path. Frequency reconfiguration is achieved by RF path selection using dc controlled p-i-n diodes. As a result, narrowband filtering responses at desired frequency bands can be achieved. One antenna prototype is simulated, fabricated, and measured. Measured reflection coefficients and radiation patterns demonstrate that the proposed reconfigurable filtering antenna is an eligible candidate for future multifunctional systems incorporating both UWB and WLAN systems.
79 citations
TL;DR: The measurement results show that the proposed antenna is with the merits of average gain of 5 dBi, stable radiation patterns, low cross polarization, and low backlobes, exhibiting potentially use for the applications of 5G wireless communication systems.
Abstract: A low-profile microstrip antenna with stable radiation pattern in a relatively wide band is presented for 5G operation. Four resonant modes with different frequencies are integrated in a single structure to enhance the bandwidth with stable gain, and well matched by introducing the folded walls. An impedance bandwidth of 58.3% has been achieved from 2.84 to 5.17 GHz with a compact structure of ${\text{0.84}}\lambda _{0}\,\times \,{\text{0.68}}\lambda _{0}\,\times \,{\text{0.06}}\lambda _{0}$ , where $\lambda _{0}$ is the free-space wavelength at the center frequency of 4 GHz. The measurement results show that the proposed antenna is with the merits of average gain of 5 dBi, stable radiation patterns, low cross polarization, and low backlobes, exhibiting potentially use for the applications of 5G wireless communication systems.
77 citations
TL;DR: In this paper, a 42-element microstrip parasitic patch antenna is developed in the millimeter-wave band for fifth-generation mobile communication base stations, which has an insertion loss of 0.045 dB.
Abstract: A 42-element microstrip parasitic patch antenna is developed in the millimeter-wave band for fifth-generation mobile communication base stations. A metalized elliptical stripline-to-embedded-microstrip transition with adaptive via-hole arrangement as well as a 20 dB Chebyshev tapered six-way power divider is proposed to have an insertion loss of 0.045 dB. To confirm the feasibility of the antenna, it has been measured to provide a 6.3% fractional bandwidth from 26.83 to 28.56 GHz at VSWR of less than 1.96. The array antenna gains of more than 21.4 dBi have been realized with sidelobe levels of better than –19.1 dB, operating within 27.5–28.5 GHz in both the azimuth and elevation directions.
76 citations
01 Feb 2018
TL;DR: In this article, a micro strip patch antenna for future 5G communication technology at centered frequency 38GHz and 54GHz having bandwidth 1.94GHz and 2GHz respectively with low cost substrate and small size patch best suited for miniaturized devices.
Abstract: This paper presents a micro strip patch antenna for future 5G-communication technology at centered frequency 38GHz and 54GHz having bandwidth 1.94GHz and 2GHz respectively with low cost substrate and small size patch best suited for miniaturized devices. It consists of Rogers RT5880 (lossy) substrate with dielectric constant 2.2 with loss tangent of 0.0013 and standard thickness 0.508mm, PEC patch and PEC ground. Substrate of dimensions 6mm×6.25mm and patch with dimensions 2mm×2mm is used. Microstrip-line feeding technique is used. Array having 4 elements with 4mm spacing has been proposed to achieve 12 dB gain for mobile data Applications on millimeter wave frequencies at 38.6GHz, 47.7GHz and 54.3GHz having bandwidth 3.5GHz, 2.5GHz and 1.3GHz respectively with Tapered line feeding. Overall size of antenna is 6mm×6.25mm×0.578mm. The proposed Antenna design is simulated on CST Microwave Studio.
74 citations
TL;DR: In this article, a single-polarized filtering dielectric resonator antenna (DRA) with high selectivity is investigated, where the DRA is fed by hybrid microstrip line/conformal strip, excited in its fundamental TE$1\delta 1}^{y} $ mode.
Abstract: A compact single-polarized filtering dielectric resonator (DR) antenna (DRA) with high selectivity is investigated. The DRA is fed by hybrid microstrip line/conformal strip, excited in its fundamental TE $_{1\delta 1}^{y} $ mode. Owing to different loading effects of the microstrip stub and conformal strip, the resonance frequency of TE $_{1\delta 1}^{y}$ mode excited by the two feed lines is slightly different. Such stepping resonances yield a wide bandwidth of 21.9% and a very flat gain of 5.1 dBi. The hybrid-feeding scheme also establishes a cross-coupled structure in the DRA, which introduces two radiation nulls right near the band edges. A compact wideband filtering DRA (FDRA) with quasi-elliptic bandpass response is, therefore, obtained without requiring any specific filtering circuit. This single-polarized design is also modified to realize a dual-polarized FDRA by adding another orthogonal port with the same feeding scheme. To reduce mutual coupling between the two ports, the microstrip stubs are folded to L shape, and four additional metal posts are inserted into the DR. As a result, the isolation is improved by 14 dB, from 7.2 to 21.2 dB.
73 citations
TL;DR: In this article, two wide-angle scanning linear array antennas (E- and H-planes scanning linear arrays antenna) are studied and presented, and a wide beamwidth U-shaped microstrip antenna with the electric walls is designed.
Abstract: Two wide-angle scanning linear array antennas (E- and H-planes scanning linear array antenna) are studied and presented. In order to improve the wide-angle scanning performance of the phased array antenna, a wide beamwidth U-shaped microstrip antenna with the electric walls is designed. The wide-angle scanning linear array antennas are studied in the frequency band from 3.2 to 3.8 GHz. The 3 dB beamwidth of the antenna is 140° in the E-plane scanning linear array center and 220° in the H-plane scanning linear array center at 3.5 GHz. The main beams of the H-plane scanning linear array antenna can scan from −90° to +90° with a gain fluctuation less than 3 dB and a maximum sidelobe level (SLL) less than −5 dB. Simultaneously, the main beam of the E-plane scanning linear array antenna can scan from −75° to +75° with a gain fluctuation less than 3 dB and SLL less than −5 dB. The H- and E-planes scanning linear array antennas with nine elements are fabricated and tested. The measured results have a good agreement with the simulation results.
TL;DR: A novel, low cost, and comprehensive microwave imaging system is presented for the detection of unwanted tumorous cells into the human breast by using AMC inspired CPW-fed antenna based microwave imaging, which can clearly detect the tumor inside the breast phantom.
Abstract: A novel, low cost, and comprehensive microwave imaging (MWI) system is presented for the detection of unwanted tumorous cells into the human breast. A compact metamaterials (MTM) artificial magnetic conductor (AMC) surface-inspired coplanar waveguide fed (CPW-fed) microstrip antenna is developed for MWI applications. The initial wideband CPW antenna is designed by the modified oval shape patch and half cycle copper stripe line ground. The antenna is incorporated with two layers uniplanar AMC structure which is composed of a $5\times 5$ array of square modified split ring resonator unit cells to obtain the desired antenna characteristics for the MWI applications like breast imaging. The metamaterial-based AMC structure improves the gain about 5 dB and produces stronger directive radiation characteristics. The enhancement of CPW performance proofs the effectiveness of the double layer MTM-AMC structure and its suitability for MWI. A microcontroller-based PC controlled alternative mechanical imaging system is designed to collect the scattering signal from the CPW-fed antenna. The changes of reflection and transmission coefficient with the variation of dielectric content into the breast phantom structure are analyzed. The remarkable deviation of scattered field is processed by image processing program using Matlab. By using these AMC inspired CPW-fed antenna based microwave imaging, the system can clearly detect the tumor inside the breast phantom.
TL;DR: In this article, a wideband circularly polarized (CP) antenna array composed of novel microstrip antenna elements is presented for IEEE 802.11 aj (45 GHz) application, achieving an impedance bandwidth of 24.9% and a 3 dB axial ratio (AR) bandwidth of 17.3%.
Abstract: A wideband circularly polarized (CP) $4 \times 4$ millimeter-wave antenna array composed of novel microstrip antenna elements is presented for IEEE 802.11 aj (45 GHz) application. Through introducing the L-shaped branches and truncated corners to the microstrip antenna element, an impedance bandwidth of 24.9% and a 3 dB axial ratio (AR) bandwidth of 17.3% are achieved. To clarify the effects of the L-shaped branches and truncated corners, the phase difference and amplitude ratios of the 180° and 90° electric field components at the point of (0,0,r) are extracted and analyzed. A simple and compact microstrip feeding network is designed to excite the CP antenna array, and two-layer PCB boards are used to implement the proposed array. The electromagnetic energy is coupled to the radiators from the feeding network through the aperture etched on the middle ground. The measured 3 dB AR bandwidth of the antenna array is 16% from 41.9 to 49.1 GHz, and the measured gain is all greater than 17 dBic within the band from 41 to 49 GHz.
TL;DR: In this article, a dual band-notched ultra wideband (UWB) multiple-input multiple-output (MIMO) antenna of size 22.26 × 26.0 × 0.8mm 3 is proposed for portable devices.
Abstract: In this paper, a novel compact dual band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna of size 22 × 26 × 0.8 mm 3 is proposed for portable devices. The antenna comprises of two stepped slot UWB antennas fed by 50 ohms microstrip line, T-shape slot and narrow slot. Dual band-notches from 5.4 to 5.86 GHz and 7.6–8.4 GHz are achieved by loading trident-shape strips on microstrip line. A T-shape slot is used on the ground plane to enhance impedance matching characteristics and to minimize mutual coupling above 4 GHz. To improve isolation further at 3–4 GHz, a narrow slot is used on ground. The proposed antenna is giving a good bandwidth ranging from 3.1 to 11.8 GHz with |S 11 | > 10 dB and mutual coupling larger than 20 dB in the entire operating band except at two rejected bands. The simulation and measurement results demonstrate that the antenna is more suitable for portable device applications.
TL;DR: The miniaturized textile antenna designed and demonstrated for ISM band applications at 2.4 GHz shows an improvement of size miniaturization and demonstrates an impedance bandwidth of 15% and efficiency of 79%, showing that it is a promising candidate for incorporation into wearable systems.
Abstract: A miniaturized textile antenna is designed and demonstrated for ISM band applications at 2.4 GHz. The proposed antenna uses appropriate loading of a rectangular slot/notch with a strip line inserted to form an inverted E-shaped antenna. The structure is simple, compact, and easy to manufacture using only fabric material. The antenna size is 75% smaller than a conventional antenna. When the antenna is subjected to bending, its performance proves sustainable under deformation. Each slot/notch and strip line is translated to its equivalent circuit and then integrated to form the whole equivalent circuit of the proposed antenna. The results from the equivalent circuits and simulation show acceptable agreement. The antenna shows an improvement of size miniaturization of $30 \times 20 \times 0.7$ mm3 and demonstrates an impedance bandwidth of 15% and efficiency of 79%, showing that it is a promising candidate for incorporation into wearable systems.
TL;DR: In this paper, a dual-band rectenna for radio frequency (RF) energy harvesting is presented, which utilizes the differential field sampling for each polarization and quadruples the overall output voltage by the rectification process.
Abstract: A dual-band rectenna for radio frequency (RF) energy harvesting is presented in this letter. The proposed antenna has two concentric square patches electrically connected with a small microstrip line connection. Four ports are located in the inner patch. The configuration of the ports enables a differential field sampling scheme and dual polarization. The antenna operates for the WiFi frequency bands of 2.4 and 5.5 GHz with 7.52 and 7.26 dBi gain, respectively, for each frequency. A full-wave Greinacher voltage doubler rectifier for each polarization has been employed for RF-to-dc conversion. The proposed novel topology utilizes the differential field sampling for each polarization and quadruples the overall output voltage by the rectification process. The differential output voltage source from the rectenna can directly act as a power source as typically electronics require differential source for their operation.
TL;DR: In this article, the authors proposed an elliptical monopole fed by a coplanar waveguide; it uses a kapton substrate and it is optimised to work from 1 to 8 GHz.
Abstract: New generations of printed flexible antennas are playing an important role in wireless communication systems. The ultra wide band and wearable possibilities are critical aspects of these kinds of antennas. In this study, the proposed antenna is an elliptical monopole fed by a coplanar waveguide; it uses a kapton substrate and it is optimised to work from 1 to 8 GHz. In the case of copper, a conductive nanocomposite material based on a polymer (polyaniline: PANI) and charged by multiwalled carbon nanotubes (MWCNTs) is exploited. The flexibility of both the kapton substrate and the nanocomposite (PANI/MWCNTs) provides the ability to crumple the antenna paving the way to potential applications for body-worn wireless communications systems. In this study, the performance of the antenna is investigated in terms of return loss, radiation patterns and gain for both crumpled and uncrumpled antennas. The results confirm that performance remains at a good level when the antenna is crumpled.
TL;DR: In this article, a circularly polarised (CP) periodic leaky-wave antenna excited by spoof surface plasmon polaritons (SPPs) is proposed, which converts the SPPs mode to CP propagating waves in the air.
Abstract: A circularly polarised (CP) periodic leaky-wave antenna excited by spoof surface plasmon polaritons (SPPs) is proposed. It is based on an SPP transmission line loaded by periodic rectangular patches on both sides with 90° phase shift, which converts the SPPs mode to CP propagating waves in the air. Due to the dispersion nature of SPPs waveguide, this leakywave antenna exhibits a beam scanning feature. Both simulated and measured results demonstrate that the proposed antenna has an impedance bandwidth of 33% for |S
11
| <; - 10dB and a 3 dB axial ratio bandwidth of 15%. The average gain and radiation efficiency are about 10 dBic and 87% from 5.5 to 6.4 GHz, respectively.
TL;DR: In this article, a compact antenna based on fractal and metamaterial loads techniques was proposed for wireless applications and the proposed antenna is suitable for reconfigurable antenna is shown in this paper.
Abstract: We have described a compact antenna based on fractal and metamaterial loads techniques. The microstrip patch antenna is assumed as a basic antenna and then the effect of fractal structures is implemented. The fractal patch is considered as a right-handed element and then by adding a left-handed element, the antenna miniaturization is achieved by using the metamaterial loads technique. The equivalent circuit is also used to describe the element effect on miniaturization and parametric models clarify them. The proposed antenna is modified for wireless applications and experimental results confirm our simulation results. In addition, we show that the proposed antenna is suitable for reconfigurable. By joining the unit cells together with various arrangements and changing the effective length, the various inductances can be obtained. Finally, by adding reconfigurable characteristic to the proposed antenna, the gain and radiation pattern can be controlled as shows in this paper. The patch antenna has low bandwidth and gain and so we have developed the patch antenna with defected ground to improve the bandwidth and the Frequency Selective Surface (FSS) is used to achieve higher gain and bandwidth. The final antenna is covering 2.4, 3.5 and 5.5 GHz with higher gain than the patch antenna.
TL;DR: In this article, the authors apply the mantle cloaking method to reduce the mutual coupling between two closely spaced wideband antennas operating at microwave frequencies, and show that by introducing two dielectric elliptical shells around the antennas and covering them with two strongly coupled elliptically shaped metasurfaces comprised of I-shaped printed unit cells, it is possible to significantly increase the original bandwidth of the antennas.
Abstract: In this paper, we apply the mantle cloaking method to reduce the mutual coupling between two closely spaced wideband antennas operating at microwave frequencies. We show that by introducing two dielectric elliptical shells around the antennas and covering them with two strongly coupled elliptically shaped metasurfaces comprised of I-shaped printed unit cells, it is possible to significantly increase the original bandwidth of the antennas and, at the same time, reduce the mutual electromagnetic interaction. This effect is observed both in a reduction of mutual S-parameters between the antennas and in the restoration of the original radiation patterns, as if the antennas were almost completely isolated from each other. Broadband metasurface/cloak designs are proposed for two geometries, with the free-standing strip monopole antennas placed over a ground plane and with the metasurface cloaks integrated with microstrip antennas.
TL;DR: In this article, the authors presented a new circular polarization reconfigurable antenna for 5G wireless communications, containing a semicircular slot, was compact in size and had a good axial ratio and frequency response.
Abstract: This paper presented a new circular polarization reconfigurable antenna for 5G wireless communications. The antenna, containing a semicircular slot, was compact in size and had a good axial ratio and frequency response. Two PIN diode switches controlled the reconfiguration for both the right-hand and left-hand circular polarization. Reconfigurable orthogonal polarizations were achieved by changing the states of the two PIN diode switches, and the reflection coefficient |S11| was maintained, which is a strong benefit of this design. The proposed polarization-reconfigurable antenna was modeled using the Computer Simulation Technology (CST) software. It had a 3.4 GHz resonance frequency in both states of reconfiguration, with a good axial ratio below 1.8 dB, and good gain of 4.8 dBic for both modes of operation. The proposed microstrip antenna was fabricated on an FR-4 substrate with a loss tangent of 0.02, and relative dielectric constant of 4.3. The radiating layer had a maximum size of 18.3 × 18.3 mm2, with 50 Ω coaxial probe feeding.
TL;DR: In this article, a novel ring-type layout of metamaterial absorber (MA) is investigated for the first time, and a three-layer MA unit cell is duplicated along the ring lattices to obtain the proposed dual-ring MA structure, which possesses desirable electromagnetic wave absorbing characteristics.
Abstract: In this letter, a novel ring-type layout of metamaterial absorber (MA) is investigated for the first time. Three-layer MA unit cell is duplicated along the ring lattices to obtain the proposed dual-ring MA structure, which possesses desirable electromagnetic wave absorbing characteristics. A center-fed circular patch antenna (CPA) coupled with the dual-ring MA is presented to produce a monopole-like radiation pattern and reduce the in-band radar cross section (RCS). MA array acts as an absorber and a radiator simultaneously in this integrated antenna. Both the simulated and measured results demonstrate that compared with the CPA with an annular ring, the in-band RCS of the proposed antenna is dramatically reduced without degradation of antenna radiation performance.
TL;DR: In this paper, a metamaterial unit cell comprises an L-shaped slit which is etched inside a rectangular patch with a grounded inductive spiral, which behaves as a series left-handed capacitance and the spiral as a shunt left-hand inductance.
Abstract: This study describes the design of a metamaterial planar antenna for multi-octave band operation. The metamaterial unit-cell comprises L-shaped slit which is etched inside a rectangular patch with a grounded inductive spiral. The slit essentially behaves as a series left-handed capacitance and the spiral as a shunt left-handed inductance. The antenna was modelled and optimised for impedance bandwidth, gain and efficiency performance using commercial three-dimensional full-wave electromagnetic simulation tools. The antenna has a measured impedance bandwidth of 6.02 GHz for S 11<−10 dB. This corresponds to a fractional bandwidth of 172.49%, which is higher than multiband planar antennas reported to date. The antenna has a maximum gain and efficiency performance of 3.7 dBi and 73%, respectively, at 3.25 GHz. The physical footprint of the antenna is comparable to other wideband planar antennas reported to date. The overall size of the antenna is 0.037λ 0 × 0.027λ 0 × 0.002λ 0 and 0.25λ 0 × 0.18λ 0 × 0.017λ 0, where λ 0 is free-space wavelength at 0.48 and 3.25 GHz, respectively.
TL;DR: In this article, a wide-scanning-angle leaky-wave antenna (LWA) based on a microstrip spoof surface plasmon polaritons (SSPPs) transmission line (TL) is proposed.
Abstract: In this letter, a wide-scanning-angle leaky-wave antenna (LWA) based on a microstrip spoof surface plasmon polaritons (SSPPs) transmission line (TL) is proposed. The dual-conductor SSPPs-TL as the guiding-wave structure of the proposed antenna consists of a two-edged grooved corrugated strip and a ground plane. A set of metallic posts connect the corrugated strip to the ground plane along two sides of the SSPPs-TL in a staggered way, which converts SSPPs to radiation waves. A power divider is the feeding network for two antenna arrays. The scanning region is mainly controlled by the depth of the groove, which has strong relationship with the dispersion of the antenna. Over the operating band from 5 to 7 GHz, the beam of the proposed antenna scans widely from −30° to 51° (including the broadside) with the realized gain varying from 15.9 to 19.4 dBi. A prototype is fabricated and measured, which confirms the design theory and the simulation results.
TL;DR: In this article, a bandwidth-enhanced circularly polarized (CP) microstrip antenna with two annular sector-shaped parasitic patches was proposed and analyzed, where the induced current on the parasitic patches involves both x and y components, hence it can control the theta and phi components of the electric field.
Abstract: This letter finds that bandwidth of a circularly polarized (CP) microstrip antenna can be enhanced by using two annular-sector-shaped parasitic patches. This is because the induced current on the parasitic patches involves both x - and y -components, hence it can control the theta and phi components of the electric field. For the purpose of demonstration, a bandwidth-enhanced CP microstrip antenna is proposed and analyzed. Except from low profile and compact size, its impedance matching can be adjusted while keeping the CP feature unchanged, which simplifies the design process. The axial-ratio bandwidth of the proposed antenna can be effectively increased from 1.3% to 3.3%, while its impedance bandwidth is increased from 4.3% to 6.0%.
TL;DR: In this article, a bandwidth-enhanced, low-cost, compact, inkjet-printed multilayer microstrip fractal patch antenna for integration into flexible and conformal devices is presented.
Abstract: This paper presents a bandwidth-enhanced, low-cost, compact, inkjet-printed multilayer microstrip fractal patch antenna for integration into flexible and conformal devices. The antenna consists of two layers of patches, with the first layer inkjet-printed directly on a 0.125-mm (only 0.005 of the operating wavelength) Kapton polyimide substrate. On top of it, a 0.12-mm-thick SU-8 polymer is covered. To achieve the desired miniaturization and good impedance match, a Minkowski fractal geometry patch is employed as the second layer inkjet-printed on top of the SU-8 polymer. The proposed antenna has compact dimensions of only $22\times 31$ mm2 and covers 4.79–5.04-GHz frequency spectrum with $S_{11} dB. Moreover, a 2-bit $1\times 4$ phased array antenna (PAA) is constructed, and its scan ability is estimated to demonstrate its potential application in the true-time-delay flexible PAA systems. The prototype is fabricated and tested for impedance and radiation characteristics. The measured and the simulation results show the superiority of the proposed antenna.
TL;DR: In this paper, the design and development of a low profile and compact single probe-fed metamaterial (MTM)-based circularly polarised (CP) antenna using the modified rectangular patch with two pairs of spiral strips and vias for 5.2/5.8 GHz WLAN applications is described.
Abstract: This work explains the design and development of a low profile and compact single probe-fed metamaterial (MTM)-based circularly polarised (CP) antenna using the modified rectangular patch with two pairs of spiral strips and vias for 5.2/5.8 GHz WLAN applications. The intended CP antenna mainly consists of two pairs of radiators and each radiator is realised by using epsilon negative (ENG) transmission line (TL) to generate zeroth-order resonance. CP characteristics are achieved by placing two radiators for x
-polarised wave are orthogonally aligned to the other two radiators for y
-polarised wave. The antenna radiating element offers a compact size of 0.24λ
0
× 0.22λ
0
with a low profile of 0.04λ
0
at 5.5 GHz. To confirm the characteristics of the intended MTM CP antenna design, the designed antenna is fabricated and measured. Measurement results show that the antenna obtains -10 dB impedance bandwidth of 610 MHz (10.86%) which is 2.3 times larger than the standard microstrip patch antenna and axial ratio bandwidth of 140 MHz (2.54%) is obtained.
TL;DR: In this article, a metamaterial-based wideband and high gain circularly polarized (CP) antenna is proposed and analyzed, which consists of a $4 \times 4$ mushroom-cells array and an L-shaped slot coupling-fed layer.
Abstract: A metamaterial-based wideband and high-gain circularly polarized (CP) mushroom antenna is proposed and analyzed in this letter. The proposed antenna consists of a $4 \times 4$ mushroom-cells array and an L-shaped slot coupling-fed layer. The metamaterial-based mushroom cells are adopted to adjust the axial ratio (AR) to realize wideband CP and high gain. With the optimization, the proposed dielectric-filled mushroom antenna is with a low profile of $0.08{\lambda _0}$ ( ${\lambda _0}$ is the operating wavelength in free space) while covering an area of $60\,{\text{mm}} \times 60\,{\text{mm}}$ only. The measured impedance bandwidth of the proposed antenna is 48.2% (5.2–8.5 GHz), and the measured 3 dB AR bandwidths are 35.5% (5.8–8.3 GHz). Moreover, the antenna performed a stable high gain which is better than 10.5 dBic from 6 to 7.5 GHz across the CP region.
TL;DR: In this paper, a series-parallel patch antenna array is presented, in which the dual-slot feeding structure is handily implemented using the intrinsic field distribution of TE20 mode in substrate-integrated waveguide (SIW).
Abstract: A millimeter-wave series–parallel patch antenna array is presented, in which the dual-slot feeding structure is handily implemented using the intrinsic field distribution of TE20 mode in substrate-integrated waveguide (SIW). One 28 GHz patch antenna element fed by the TE20-mode SIW is first designed, achieving a 10 dB impedance bandwidth of 10.2% and a simulated peak gain of 6.48 dBi. Based on the antenna element, a $4 \times 4$ array with a compact series–parallel differential feeding network is developed accordingly. Due to the novel compact SIW-based series–parallel feeding network, the antenna array can achieve superior radiation performances, which is the highlight of this communication. The simulation and measurement results of the proposed antenna array are in good agreement, demonstrating a performance of 8.5% impedance bandwidth, 19.1 dBi peak gain, symmetrical radiation patterns, and low cross-polarization levels (−30 dB in E-plane and −25 dB in H-plane) in the operating frequency band of 26.65–29.14 GHz.
TL;DR: A wideband wearable button antenna working around 2.4 GHz that provides robustness across different environments and to relatively large fabrication tolerances is proposed.
Abstract: A wideband wearable button antenna working around 2.4 GHz is proposed in this paper. The function of the textile antenna ground is analyzed based on characteristic mode theory. By properly locating the button on the ground, the latter can be efficiently excited and operates as a radiator. This is shown to greatly increase the impedance bandwidth. The antenna is analyzed both in free space and on the human body. A prototype is fabricated, and the measured results agree satisfactorily with the simulations. In free space, the bandwidth, the realized gain, and radiation efficiency are 658 MHz, 1.8 dBi, and 97%, respectively. While on the human body, the values can reach 788 MHz, 5.1 dBi, and 71%, respectively. This wide band behavior provides robustness across different environments and to relatively large fabrication tolerances. The specific absorption rate is below 0.45 W/kg for an equivalent isotropically radiated power of 20 dBm.