Showing papers on "Microstrip antenna published in 2015"
TL;DR: In this article, a novel kind of patch antenna with high-selectivity filtering responses and high-gain radiation performance is presented, which is mainly composed of a driven patch and a stacked patch, with its entire height being ${0.09\lambda }$.
Abstract: This paper presents a novel kind of patch antenna with high-selectivity filtering responses and high-gain radiation performance. The proposed antenna is mainly composed of a driven patch and a stacked patch, with its entire height being ${0.09\lambda }$ . Three shorting pins and a U-slot are embedded in the driven patch to enhance out-of-band suppression levels and skirt selectivity near the lower band-edge, whereas the stacked patch provides a sharp roll-off rate at the upper band-edge and also an enhanced gain. Without using extra filtering circuits, the proposed antenna exhibits a quasi-elliptic boresight gain response with three radiation nulls. For demonstration, an antenna is implemented covering the LTE band (2.3–2.7 GHz). The antenna achieves an average gain of 9.7 dBi within passband, and out-of-band suppression levels of more than 21 dB.
330 citations
01 Jan 2015
TL;DR: In this article, the authors focused on circularly polarized antennas and provided key definitions and governing equations of circular polarization, and extended the concept to the magnetic source counterparts and Huygens sources.
Abstract: This chapter is focused on circularly polarized antennas. Key definitions and governing equations of circular polarization are given. Infinitesimal dipole sources are considered to establish circularly polarized radiation. First, radiation patterns of cross dipoles are mathematically reviewed, from which the condition of circularly polarized waves is concluded. Later, the idea is extended to four displaced sequentially rotated dipole antennas, resulting in circularly polarized waves within a wide angular range in space. The extension of the concept to the magnetic source counterparts and Huygens sources is briefly discussed. Other than point sources, also known as one-dimensional current sources, sources of circularly polarized radiation are further investigated for two-dimensional cases, such as microstrip patch antennas, and threedimensional structures, such as volumetric current sources existing in dielectric resonator antennas. For these cases, the creation of circularly polarized radiation using single-feed and dual-feed, perturbed structures and sequentially rotated method is described. As a design example, numerical andmeasurement results of circularly polarized square patch ring antennas are extensively discussed and presented in this chapter. The square-ring microstrip antenna is selected as it closely approximates the sequentially rotated currents, and also it has not been widely studied in the literature.
327 citations
TL;DR: In this paper, a metamaterial-based broadband low-profile grid-slotted patch antenna is presented, where a periodic array of series capacitor-loaded patch cells is formed, and excited through the coupling aperture in a ground plane right underneath and parallel to the slot at the center of the patch.
Abstract: A metamaterial-based broadband low-profile grid-slotted patch antenna is presented. By slotting the radiating patch, a periodic array of series capacitor loaded metamaterial patch cells is formed, and excited through the coupling aperture in a ground plane right underneath and parallel to the slot at the center of the patch. By exciting two adjacent resonant modes simultaneously, broadband impedance matching and consistent radiation are achieved. The dispersion relation of the capacitor-loaded patch cell is applied in the mode analysis. The proposed grid-slotted patch antenna with a low profile of $0.06 \lambda_{0}$ ( $\lambda_{0}$ is the center operating wavelength in free space) achieves a measured bandwidth of 28% for the $\vert{\text{S}_{{11}}}\vert$ less than $-{10}\;\text{dB}$ and maximum gain of 9.8 dBi.
239 citations
TL;DR: In this paper, a bandwidth-enhanced, compact, monopole antenna with modified ground plane for modern automotive ultra wideband (UWB) applications is presented, where the ground plane of the fundamental radiator is curved and defected to improve the VSWR bandwidth.
Abstract: This communication presents a bandwidth-enhanced, compact, monopole antenna with modified ground plane for modern automotive ultra wide-band (UWB) applications The proposed antenna has hybrid geometry and is constructed using half circular ring and half square ring The ground plane of the fundamental radiator is curved and defected to improve the VSWR bandwidth An extended ground stub is added to further enhance the bandwidth to suit the modern automotive requirements The designed antenna covers 31–109 GHz frequency spectrum with ${\mathrm {VSWR}} \leq {2}$ This antenna can be conveniently placed inside the shark fin housing or it can be printed along with the existing print circuit board (PCB) electronics nullifying the need for dedicated location for in-car communications Furthermore, a simple two-port multiple input multiple output (MIMO) antenna is constructed and its diversity performance is estimated The prototype is fabricated and tested for impedance and radiation characteristics
225 citations
TL;DR: In this article, a high-gain transmitting lens antenna by employing layered phase-gradient metasurface (MS) was proposed to focus the propagating plane wave to a point with high efficiency.
Abstract: We propose a high-gain transmitting lens antenna by employing layered phase-gradient metasurface (MS). The MS is engineered to focus the propagating plane wave to a point with high efficiency. An X-band patch antenna is placed at the focal point of the MS as a feed source, and then the quasi-spherical wave emitted by the source is transformed to plane wave. Due to the successful conversion of quasi-spherical wave to plane wave, the beam width of the patch antenna has been decreased 66° and the gain has been enhanced 11.6 dB. The proposed lens antenna not only opens up a new route for the applications of phase-gradient MS in microwave band, but also affords an alternative for high-gain antenna.
189 citations
TL;DR: In this article, the authors proposed a new antenna structure based on a parasitic elliptical patch in the flare aperture to enhance the field coupling between the arms and produce stronger radiation in the end-fire direction.
Abstract: Herein, a new method for improving the directivity and bandwidth of the antipodal Vivaldi antenna structure is presented. The method is based on introducing a parasitic elliptical patch in the flare aperture to enhance the field coupling between the arms and produce stronger radiation in the endfire direction. This approach improves the directivity without compromising the low frequency performance and removes the need for electrically thin dielectric substrates. The proposed antenna structure including the feeding line and transition measures $140 \times 66 \times 1.5 \text{mm}^3$ and has a peak gain $> 0\;{\text{dBi}}$ over the 2–32 GHz frequency range and ${>} 10\;{\text{dBi}}$ over the 6–21 GHz range, which is an improvement to what has been reported for Vivaldi antennas with similar size.
183 citations
TL;DR: In this article, a compact multiple-input-multiple-output (MIMO) antenna with band-notched function is presented for ultrawideband (UWB) applications.
Abstract: A compact multiple-input–multiple-output (MIMO) antenna is presented for ultrawideband (UWB) applications with band-notched function. The proposed antenna is composed of two offset microstrip-fed antenna elements with UWB performance. To achieve high isolation and polarization diversity, the antenna elements are placed perpendicular to each other. A parasitic T-shaped strip between the radiating elements is employed as a decoupling structure to further suppress the mutual coupling. In addition, the notched band at 5.5 GHz is realized by etching a pair of L-shaped slits on the ground. The antenna prototype with a compact size of $38.5 \times38.5~\hbox{mm}^{2}$ has been fabricated and measured. Experimental results show that the antenna has an impedance bandwidth of 3.08-11.8 GHz with reflection coefficient less than $-10~\hbox{dB}$ , except the rejection band of 5.03-5.97 GHz. Besides, port isolation, envelope correlation coefficient and radiation characteristics are also investigated. The results indicate that the MIMO antenna is suitable for band-notched UWB applications.
174 citations
TL;DR: Cavity-backed patch antenna arrays with full corporate substrate integrated waveguide (SIW) feed networks are demonstrated at V-band for applications with the needs of high-gain antennas.
Abstract: Cavity-backed patch antenna arrays with full corporate substrate integrated waveguide (SIW) feed networks are demonstrated at V-band for applications with the needs of high-gain antennas. A prototype of $16 \times 16$ radiating elements with a waveguide transition is fabricated by applying standard printed circuit board (PCB) facilities. A gain up to 30.1 dBi with a 3-dB gain bandwidth of 16.1%, an impedance bandwidth of 15.3% for $\mathrm{SWR} \,{ , and symmetrically broadside radiation patterns with $-40\,\mathrm{dB}$ cross-polarizations are achieved. The performance of the proposed antenna array is also systematically evaluated. The result serves as a reference for designing large antenna arrays operating at millimeter-wave frequencies.
174 citations
TL;DR: In this article, a multimode filtering antenna, which is realized by integrating a multi-modal resonator and an antenna, has been applied to the design of dual-polarized antenna arrays for achieving a compact size and high performance in terms of broad bandwidth, high-frequency selectivity and out-of-band rejection.
Abstract: A novel design concept of multimode filtering antenna, which is realized by integrating a multimode resonator and an antenna, has been applied to the design of dual-polarized antenna arrays for achieving a compact size and high performance in terms of broad bandwidth, high-frequency selectivity and out-of-band rejection. To verify the concept, a $2 \times 2$ array at C-band is designed and fabricated. The stub-loaded resonator (SLR) is employed as the feed of the antenna. The resonant characteristics of SLR and patch as well as the coupling between them are presented. The method of designing the integrated resonator-patch module is explained. This integrated design not only removes the need for separated filters and traditional ${50}{\text - }{\Omega }$ interfaces but also improves the frequency response of the module. A comparison with the traditional patch array has been made, showing that the proposed design has a more compact size, wider bandwidth, better frequency selectivity, and out-of-band rejection. Such low-profile light weight broadband dual-polarized arrays are useful for space-borne synthetic aperture radar (SAR) and wireless communication applications. The simulated and measured results agree well, demonstrating a good performance in terms of impedance bandwidth, frequency selectivity, isolation, radiation pattern, and antenna gain.
166 citations
TL;DR: In this article, a dual-band wearable fractal-based monopole patch antenna integrated with an electromagnetic band-gap (EBG) structure is presented for the GSM-1800 MHz and ISM-2.45 GHz bands.
Abstract: This letter presents the design of a dual-band wearable fractal-based monopole patch antenna integrated with an electromagnetic band-gap (EBG) structure. The prototype covers the GSM-1800 MHz and ISM-2.45 GHz bands. The EBG structure reduces the radiation into the human body over 15 dB. It also reduces the effect of frequency detuning due to the human body. The performance of the antenna under bending, crumpling, and on-body conditions has been studied and presented. Specific absorption rate (SAR) assessment has also been performed to validate the antenna for its usefulness in wearable applications.
160 citations
TL;DR: A novel dual-band, dual-polarized, miniaturized and low-profile base station antenna operating in the frequency bands of 820-960 and 1710-2170 MHz is designed that meets the stringent design requirements and also meets telecommunications industry standards.
Abstract: In this paper, a novel dual-band, dual-polarized, miniaturized and low-profile base station antenna operating in the frequency bands of 820–960 and 1710–2170 MHz is designed. Elements are arranged such that high-frequency elements are embedded in low frequency elements to reduce volume. A baffle is used to reflect the transmitted power density in the forward direction and also improve isolation between elements. Therefore, surrounding isolation baffles and rectangular baffles are appended around high-frequency elements and low-frequency elements, respectively. The diameter of the proposed antenna cover is only 200 mm, which is smaller than the existing antenna diameter of 280 mm. Compared with the other commonly used antennas, the proposed antenna also has some advantages such as concealment and low profile using a tubular form of radome, which can easily integrate the proposed antenna with the surrounding environment. The measured results verify that the proposed antenna meets the stringent design requirements: voltage standing wave ratio (VSWR) is less than 1.3, the isolation is greater than 30 dB, and the pattern parameters also meet telecommunications industry standards.
TL;DR: In this article, two different artificial magnetic conductor (AMC) unit cells are designed to obtain 180 $^\circ $ ( $ \pm 30^ √circ $ ) reflection phase difference over broadband frequency range.
Abstract: A design approach aimed at reducing the radar cross section (RCS) of microstrip antenna in wide frequency band is proposed. First, two different artificial magnetic conductor (AMC) unit cells are designed to obtain 180 $^\circ $ ( $ \pm 30^\circ $ ) reflection phase difference over broadband frequency range. Then, chessboard configuration is structured with the two AMC unit cells and is applied to a microstrip antenna for RCS reduction. The simulated results indicate that the proposed antenna possesses remarkable RCS reduction from 8.0 GHz to 20.0 GHz for both polarizations, covering the working band of the original antenna. The maximum reduction is 31.9 dB. Moreover, the radiation performance of the antenna has been well kept. Measured results of the fabricated prototype are in good agreement with the simulations.
TL;DR: A wideband high-gain high-efficiency hybrid integrated plate array antenna for inter-satellite links is presented in this paper, which consists of microstrip patches, substrate integrated waveguide (SIW) and waveguide power dividers.
Abstract: A wideband high-gain high-efficiency hybrid integrated plate array antenna for inter-satellite links is presented in this paper This antenna consists of microstrip patches, substrate integrated waveguide (SIW) and waveguide power dividers A novel feeding structure is proposed to excite the microstrip sub-array with a wideband characteristic The radiation efficiency of SIW arrays with different sizes is compared by experiment The hybrid SIW-waveguide feeding topology is optimized to realize high efficiency, low cost and compact configuration at the same time The array antenna is fabricated through standard multi-layer PCB process and milling technology Measured results demonstrate about 146% of reflection coefficient bandwidth ( $\vert {\rm S}_{11}\vert dB) in the frequency band of 57–66 GHz The gain fluctuates less than 3 dB within the same band The 1 dB gain bandwidth is 81% within the frequency band of 59–64 GHz The maximum gain is 392 dBi at 59 GHz with the efficiency of 41%
Patent•
11 Nov 2015
TL;DR: In this article, a co-planar waveguide feed broadband circular polarization microstrip antenna is proposed to ensureing to possess less volume under the condition of bandwidth, and market perspective.
Abstract: The utility model provides a co -planar waveguide feed broadband circular polarization microstrip antenna, including medium base plate, L type floor, L type ground connection microstrip strip and Y type microstrip feeder, the lower extreme of Y type microstrip feeder extends to the lower limb department formation feed end of medium base plate, be provided with the harmonious microstrip strip of rectangle on the lower extreme right side of Y type microstrip feeder, lower extreme right side at Y type microstrip feeder is equipped with the rectangle floor, the feed end is between L type floor and rectangle floor, be connected with the ground joint line between L type floor and rectangle floor, and at the left side of medium base plate edge, the upside is marginal and right side edge all is equipped with folding section, the both ends of L type ground connection microstrip strip are the both sides edge of perpendicular to place apex angle department respectively, and the folding section at left side edge is in the L in upper left corner type ground connection microstrip strip, and the folding section of right side edge is in the L in lower right corner type ground connection microstrip strip. This microstrip antenna is ensureing to possess less volume under the condition of bandwidth, and market perspective is better.
Patent•
12 Mar 2015TL;DR: In this paper, a rectenna according to the present invention includes a circularpolarized patch antenna having dual slots fed by a microstrip and configured to receive and output a radio frequency (RF) signal, and a rectifying circuit configured to convert for output the RF signal, received by the circular-polarised patch antenna, into a direct current (DC) signal and transfer the DC signal from the antenna to a load, wherein the rectification circuit comprises at least one radial stub.
Abstract: A rectenna according to the present invention includes a circular-polarized patch antenna having dual slots fed by a microstrip and configured to receive and output a radio frequency (RF) signal, and a rectifying circuit configured to convert for output the RF signal, received by the circular-polarized patch antenna, into a direct current (DC) signal and transfer the DC signal from the antenna to a load, wherein the rectifying circuit comprises at least one radial stub.
TL;DR: In this paper, a dual-band three-pole Chebyshev filtering patch antenna with orthogonal polarizations in the two bands is developed for 2.4/5.8 GHz ISM-band applications.
Abstract: A compact dual-band three-pole Chebyshev filtering patch antenna with orthogonal polarizations in the two bands is developed for 2.4/5.8-GHz ISM-band applications. Step impedance resonators and aperture coupled feed techniques are integrated together to fulfill the goal. The synthesis procedure is discussed using formulation and design curves. The advantages of the proposed design, including harmonic suppression and controllable bandwidth, are verified by experiments. According to the summary table, this dual-band filtering antenna, realized in planar form, shows either a more compact size or improved radiation characteristics when compared with those reported in the open literature.
TL;DR: In this article, a stub-loaded microstrip patch antenna with reconfigurable operation in both frequency and polarization is presented, using 12 varactors with two independent voltages, achieving a fractional bandwidth of around 40% while allowing selection between circular polarization with both rotating senses and linear polarization (LP).
Abstract: A stub-loaded microstrip patch antenna with reconfigurability in both frequency and polarization is presented. Using 12 varactors with two independent voltages, reconfigurability is achieved in a fractional bandwidth of around 40% while allowing selection between circular polarization (CP) with both rotating senses and linear polarization (LP). The design is optimized based on an analytical model, which significantly speeds up the process while yielding reasonably accurate predictions. For illustration of the concept, an antenna is designed, optimized, and manufactured for reconfigurable operation in the 2.4–3.6 GHz frequency range. A good agreement between simulations and measurements is obtained which validates the proposed method. A full reconfigurability is demonstrated in the operation band with the ability to both tune the antenna to a given frequency and select a polarization state among left-hand or right-hand CP or various states of LP.
TL;DR: In this article, a stair-shaped dielectric resonator antenna (DRA) with a wideband circular polarization (CP) radiation is introduced for wireless local area network (WLAN) applications.
Abstract: A circularly polarized stair-shaped dielectric resonator antenna (DRA) with a wideband circular polarization (CP) radiation is introduced for wireless local area network (WLAN) applications. This antenna is implemented by using two rectangular dielectric resonators (DRs), which are joined together to form a stair-shaped dielectric resonator antenna (DRA). In this structure, the excitation of multiple orthogonal modes leads to a wideband CP bandwidth. Measured results show that the proposed antenna has an axial ratio (AR) bandwidth of 22% (5.2–6.5 GHz), an impedance bandwidth of 37% (4.6–6.7 GHz), and a peak gain of 5.7 dB. In addition, the antenna radiation efficiency of more than 90% is achieved.
TL;DR: In this paper, a broadband monopole antenna with circular polarization (CP) is designed and fabricated, which consists of a C-shaped monopole, an open-loop on the backside of the monopole and a modified ground plane.
Abstract: A novel broadband monopole antenna with circular polarization (CP) is designed and fabricated. It consists of a C-shaped monopole, an open-loop on the backside of the monopole and a modified ground plane. By placing a rectangular open-loop coplanar with the ground plane and connecting a rectangular vertical stub to the ground plane, wide impedance bandwidth is achieved, and axial-ratio (AR) bandwidth of the antenna could be improved simultaneously. The measured results exhibit a 65.2% (4.14 GHz, 4.28–8.42 GHz) CP bandwidth, and the 10-dB impedance bandwidth is 87.7% (6.66 GHz, 4.26–10.92 GHz). Finally, by placing a reflector underneath the antenna with its structural dimensions unchanged, one can obtain unidirectional radiation patterns with greatly improved gains. The advantages of the proposed antenna are the simple structure, a compact size, and a broad 3-dB AR bandwidth.
TL;DR: In this paper, a differential microstrip antenna with improved gain for RF energy harvesting is presented, which can be used in either center grounded or differential configuration for GSM900 band (890-960 MHz).
Abstract: A differential microstrip antenna with improved gain for RF energy harvesting is presented in this paper. The developed antenna can be used in either center grounded or differential configuration. The antenna is designed and fabricated for GSM900 band (890–960 MHz). The antenna has a gain of 8.5 dBi at the center frequency and exhibits VSWR $\boldsymbol{\leq} 2$ for frequencies between 870 MHz to 1.05 GHz. The efficiency of the antenna is 80%. The developed antenna finds its application in energy harvesting, RFID tags and in wireless communication circuits, where differential inputs/outputs are needed. A complete differential RF energy harvesting system with a peak efficiency of 65.3% for a load of $3 {\mathbf{k}}\boldsymbol{\Omega}$ is also developed.
TL;DR: A study on the bandwidth performance of the proposed design reveals that wide bandwidth can be achieved for the antenna by choosing a thick supporting substrate between the water patch and the ground plane, and can be conveniently integrated with the solar cells to realize a dual-function design.
Abstract: A novel water dense dielectric patch antenna (DDPA) fed by an L-shaped probe is proposed and investigated. In contrast to the water antennas in the literature, including the water monopole and the water dielectric resonator antenna, the operation mechanism of the proposed water DDPA is similar to the conventional metallic patch antenna. The antenna is excited in a mode like the TM $_{{\textrm {10}}}$ mode of the rectangular patch antenna. An L-shaped probe, which is widely used for the conventional patch antenna, is used to excite the water DDPA. A study on the bandwidth performance of the proposed design reveals that wide bandwidth can be achieved for the antenna by choosing a thick supporting substrate between the water patch and the ground plane. A prototype is fabricated to confirm the correctness of the design. An impedance bandwidth of 8%, maximum gain of 7.3 dBi, radiation efficiency up to 70%, and symmetrically unidirectional patterns with low backlobe and low cross polarization levels are obtained. Furthermore, owing to the transparency of the water patch, the proposed water DDPA can be conveniently integrated with the solar cells to realize a dual-function design. Measurements on the prototype demonstrate that the existence of the solar cells does not significantly affect the performance of the antenna and vice versa.
TL;DR: In this article, an energy harvesting at 35 GHz has been developed, which known as a rectenna, an array of a rectangular microstrip patch antenna with 16 elements was used to efficiently convert RF to dc signal, and a step-impedance low-pass filter was used between the antenna and rectifier circuit to suppress second-order harmonic generated by the diode.
Abstract: In this letter, an energy harvester at 35 GHz has been developed, which known as a rectenna. An array of a rectangular microstrip patch antenna with 16 elements was used to efficiently convert RF to dc signal. A step-impedance low-pass filter is used between the antenna and rectifier circuit to suppress second-order harmonic generated by the diode. A GaAs Schottky diode MA4E1317 was used in parallel with load as a half-wave rectifier circuit. The fabrication process is based on conventional optical photolithography to obtain an integrated circuit. The maximum RF-to-dc conversion efficiency of 67% was successfully achieved with input RF power of 7 mW at 35.7 GHz.
TL;DR: In this paper, a patch antenna with parasitic strips is presented for wideband circular polarization, in which four parasitic strips are sequentially rotated and gap-coupled around the patch.
Abstract: A patch antenna with parasitic strips is presented for wideband circular polarization. In order to broaden the axial-ratio (AR) bandwidth of the original corner-truncated patch, four parasitic strips are sequentially rotated and gap-coupled around the patch. A capacitive-coupled feed with a small disc on the top of the feeding probe is utilized to obtain a wide impedance-matching bandwidth. Moreover, another disc-loaded shorting pin is placed at the center of the antenna to adjust the squint beams and improve the gains along $ + z$ -axis. Measured results show that the proposed antenna with a low profile of $0.13{\lambda _0}$ obtains a global bandwidth of 24% (2.32–2.95 GHz) for $\vert{S_{11}}\vert , ${\rm AR} , and average gain of 8 dBic.
TL;DR: Simulation results show improved DOA estimation accuracy and robustness using microstrip patch antennas as opposed to conventional dipoles and it is shown that the bandwidth of a UCA forDOA estimation is limited only by the broadband characteristics of the directional antenna elements and not by the electrical size of the array.
Abstract: The effect of directional antenna elements in uniform circular arrays (UCAs) for direction of arrival (DOA) estimation is studied in this paper. While the vast majority of previous work assumes isotropic antenna elements or omnidirectional dipoles, this work demonstrates that improved DOA estimation accuracy and increased bandwidth is achievable with appropriately-designed directional antennas. The Cramer–Rao Lower Bound (CRLB) is derived for UCAs with directional antennas and is compared to isotropic antennas for 4- and 8-element arrays using a theoretical radiation pattern. The directivity that minimizes the CRLB is identified and microstrip patch antennas approximating the optimal theoretical gain pattern are designed to compare the resulting DOA estimation accuracy with a UCA using dipole antenna elements. Simulation results show improved DOA estimation accuracy and robustness using microstrip patch antennas as opposed to conventional dipoles. Additionally, it is shown that the bandwidth of a UCA for DOA estimation is limited only by the broadband characteristics of the directional antenna elements and not by the electrical size of the array as is the case with omnidirectional antennas.
TL;DR: In this article, the authors describe the design of a novel planar multiple-input-multiple-output (MIMO) antenna with a canonical two-port antenna that can be replicated and concatenated together to form MIMO antennas with arbitrary even numbers of ports.
Abstract: In this paper, we describe the design of a novel planar multiple-input-multiple-output (MIMO) antenna. The basic idea of the design is the development of a canonical two-port antenna that can be replicated and concatenated together to form MIMO antennas with arbitrary even numbers of ports. The design of the canonical element uses compact folded slots for the radiating elements but includes the use of field cancelation to enhance isolation by incorporating a coupling parasitic element. In addition by properly designing the coupling parasitic and the two-port antenna, coupling between canonical elements is also reduced allowing them to be concatenated together. The canonical element size is $27.5 \times 30\;{\rm mm}^2$ operating at 2.6 GHz and it can be packed together with high densities of up to 22 elements per square wavelength. To validate the design, results from 20-port planar printed MIMO antennas are presented operating at 2.6 GHz with a bandwidth of 100 MHz. The 20-port antenna has size of $1.3{\lambda}_{0} \times 0.69{\lambda}_{0}\;{\rm mm}^2$ providing an antenna density of 22 antenna in free space square wavelength ( ${\lambda}_{0}^{2}$ ). Even though the individual antennas are densely packed, all combinations of mutual couplings between ports exhibit better than 10 dB isolation. The antennas are printed on an FR-4 printed circuit board (PCB), which is a low-cost substrate and allows straightforward prototyping.
TL;DR: A printed antenna with frequency and pattern reconfiguration is presented in this letter to meet the requirements of IEEE 802.11a/b/g/n and 802.16 standards and provides a low-profile, low-cost, and reconfigurable solution for multistandard wireless communication applications.
Abstract: A printed antenna with frequency and pattern reconfiguration is presented in this letter to meet the requirements of IEEE 802.11a/b/g/n and 802.16 standards. By controlling five p-i-n diodes, the antenna can be considered as a planar monopole or a microstrip patch and has three operation modes, i.e. an omnidirectional pattern mode at the lower frequency band of 2.21–2.79 GHz, a unidirectional pattern mode at the higher frequency band of 5.27–5.56 GHz, and both of them working simultaneously. It provides a low-profile, low-cost, and reconfigurable solution for multistandard wireless communication applications.
TL;DR: In this article, a magneto-electric dipole antenna for 60 GHz millimeter-wave applications is proposed, which exhibits an impedance bandwidth of 51% and a gain of approximately 8 dBi.
Abstract: A new wideband magneto-electric dipole antenna is proposed for 60-GHz millimeter-wave applications. This antenna features wideband and stable gain characteristics. The low cross polarization and low back radiation are obtained owing to its complementary antenna structure. The prototype of the single element was built using the low-cost single-layer printed circuit board (PCB) technology. The proposed antenna exhibits an impedance bandwidth of 51% ( ${\rm SWR} \leq 2$ ) and a gain of approximately 8 dBi.
TL;DR: In this paper, a new design approach for a microstrip patch antenna to achieve reconfigurable dual-band operation with tunable frequency ratio is introduced, which uses a lumped capacitor in the middle of a slotted patch antenna, which results in two resonant frequencies.
Abstract: A new design approach for a microstrip patch antenna to achieve reconfigurable dual-band operation with tunable frequency ratio is introduced. The approach uses a lumped capacitor in the middle of a slotted patch antenna, which results in two resonant frequencies. The two resonant frequencies and their ratio are functions of the capacitance value. If a varactor with an appropriate biasing network is used, electronic tuning is realized by changing the applied DC voltage. To understand the dual-resonance behavior of the proposed antenna, an equivalent circuit model based on the transmission line theory of the antenna is established, considering the slot effect and the lumped capacitor. The results are verified with full wave simulation. Furthermore, measurements for fabricated antenna prototypes operating in 2–4.5 GHz are carried out for validation, and the performance shows a tunable frequency ratio from 1.45 to 1.93 with a capacitance range from 0.31 to 0.74 pF. It is worthwhile to point out that the radiation patterns are similar at both bands because both resonances are due to the fundamental TM01 mode.
TL;DR: In this paper, a wideband compact circularly polarized (CP) dielectric resonator antenna (DRA) is proposed, which is excited by an aperture coupled through a slot cutting on the ground plane.
Abstract: In this letter, a wideband compact circularly polarized (CP) dielectric resonator antenna (DRA) is proposed. This antenna consists of two rectangular dielectric layers that are stacked with a rotation angle $\varphi $ relative to its adjacent bottom layer. The antenna is excited by an aperture coupled through a slot cutting on the ground plane. The rotated-stair configuration of DRA contributes dual broadside CP radiating modes and results in a noticeable enhancement in the axial ratio (AR) bandwidth. The proposed antenna achieves 31% impedance bandwidth and 18.2% AR bandwidth. The average gain within the AR bandwidth is 4.5 dBi with less than 0.5-dB variation. Moreover, the proposed dielectric resonator antenna has a low-profile structure. This work demonstrates a CP bandwidth broadening technique for the DRA. The potential applications of the antenna are 5G Wi-Fi and satellite communication systems.
TL;DR: In this article, a design concept of integrating the loop antenna into the front metal frame of a smartwatch Bluetooth device is introduced, which can easily cover the 2.4 GHz band (2400-2485 MHz) for Bluetooth operation.
Abstract: A design concept of integrating the loop antenna into the front metal frame of a smartwatch Bluetooth device is introduced. The antenna was constructed from a 0.3-mm-thick, rectangular metal frame with a dimension of $5\;{\text{mm}} \times 40\;{\text{mm}} \times 50\;{\text{mm}}$ , which encircled the system circuit board of the watch. A separation distance of 2 mm between the loop and the system ground plane was also set to alleviate the strong coupling between the antenna and the ground. With the signal feeding fixed in the middle of either one of the frame’s longer edges and followed by shorting the loop in a proper location, the antenna can easily cover the 2.4-GHz band (2400–2485 MHz) for Bluetooth operation. The design and the results thereof are described and discussed in the article.