Showing papers on "Dipole antenna published in 2018"
TL;DR: In this article, a low profile dual-polarized dipole antenna using wideband artificial magnetic conductor (AMC) reflector with stable radiation pattern for use in 2G/3G/4G base stations operating from 1.7 to 2.7 GHz is presented.
Abstract: A low-profile dual-polarized dipole antenna using wideband artificial magnetic conductor (AMC) reflector with stable radiation pattern for use in 2G/3G/4G base stations operating from 1.7 to 2.7 GHz is presented. The antenna consists of a pair of crossed-dipoles and a wideband AMC reflector which consists of an AMC surface, a metallic ground plane, and the air substrate between them. The AMC is designed to operate with 90° reflection-phase bandwidth of 1.64–2.88 GHz (54.8%). Compared with using perfect electric conductor reflector, the profile height of the dual-polarized dipole antenna using AMC reflector is reduced by half from 36 to 18 mm, resulting in the lowest-profile 2G/3G/4G base station antenna. Six metallic ground walls are used to stabilize the radiation pattern, and the resulted half-power beamwidths are around 68±3° and 81±3° in the H- and V-planes, respectively, across the operating band. More measured results show that wide impedance bandwidths of 1.67–2.98 and 1.64–3.05 GHz for the two input ports, isolation of more than 25 dB, and cross-polarization of less than −20 dB are achieved.
128 citations
TL;DR: This letter proposes a novel pattern-reconfigurable antenna that provides an efficient solution for wireless communications by reconfiguring parasitic striplines placed around a radiating dipole and reflecting metal pieces under the dipole using p-i-n diodes.
Abstract: Pattern-reconfigurable antennas with multiple switchable beams, especially with both boresight and endfire directions, are highly desired for wireless communications. In this letter, a novel pattern-reconfigurable antenna is proposed that provides an efficient solution. By reconfiguring parasitic striplines placed around a radiating dipole and reflecting metal pieces under the dipole using p-i-n diodes, the antenna main beam can be switched to five directions in the elevation plane, approximately from $-90^{\circ }$ (left endfire), $-45^{\circ }$ , 0 $^{\circ }$ (boresight), $+45^{\circ }$ , to $+90^{\circ }$ (right endfire). The proposed antenna operates at 2.45 GHz with dimensions of about 0.57 $\lambda$ $\times\, 0.45\lambda$ $\times\, 0.28\lambda$ . An antenna prototype is fabricated and measured. For all five directional beams, the measured $|S_{11}|$ values are below $-$ 13 dB, and the measured realized gains range from 5.2 to 6.5 dBi. They agree reasonably well with the simulated ones.
116 citations
TL;DR: In this article, a broadband dual-polarized filtering dipole antenna for base station application is presented, which consists of four parts: main radiator, feeding baluns, reflector, and two parasitic loops.
Abstract: This paper presents a broadband dual-polarized filtering dipole antenna for base-station application, which has a compact size of 50 $\text {mm} \times 50\,\,\text {mm} \times 31.8$ mm. The antenna consists of four parts: main radiator, feeding baluns, reflector, and two parasitic loops. Without using complex filtering circuits, the dual-polarized dipole antenna realizes satisfactory filtering performance and enhanced bandwidth by employing only two parasitic loops. Two specific radiation nulls are thus generated and individually controlled by the two parasitic loops. To further improve the upper stopband selectivity and bandwidth, a simple open-ended stub is added to the arms of the dipole. As a result, the bandwidth can be tuned from 7.4% to 47.6%, and the realized gain is decreased dramatically from 8.6 dBi at 2.7 GHz (in-band) to −10 dBi at 2.9 GHz (out-of-band). For demonstration, a broadband dual-polarized dipole antenna is implemented. Measured results show that the proposed antenna has more than 34 dB port isolation over 48.7% (1.66–2.73 GHz) impendence bandwidth (VSWR < 1.5). The measured in-band gain is about 8.15 dBi with stable 3 dB beamwidth 65.4°±2.4° in the horizontal plane, whereas the out-of-band radiation suppression is more than 17 dB.
108 citations
TL;DR: In this article, a triple band differential rectenna for RF energy harvesting applications is proposed, which is designed to operate in frequency bands of universal mobile telecommunication service (2.1 GHz), lower WLAN/Wi-Fi (2, 2.48 GHz), and WiMAX (3.3-3.8 GHz).
Abstract: A triple band differential rectenna for RF energy harvesting applications is proposed in this paper. The rectenna is designed to operate in frequency bands of universal mobile telecommunication service (2.1 GHz), lower WLAN/Wi-Fi (2.4–2.48 GHz), and WiMAX (3.3–3.8 GHz). For designing the proposed rectenna, first a differentially fed multiband slot antenna that works as the front-end receiving unit is designed, fabricated, and tested to check its performance. It is observed that a peak antenna gain of 7, 5.5, and 9.2 dBi is achieved at 2, 2.5, and 3.5 GHz, respectively. In the next step, a triple band differential rectifier is designed using the Villard voltage doubler where interdigital capacitors (IDCs) in lieu of lumped components are used. The full rectifier circuit comprising of the rectifying unit and impedance matching circuit is fabricated and tested to check its performance in the desired bands. The peak RF-dc conversion efficiency of 68% is obtained using the three-tone measurement. In the final stage, both antenna and the rectifier circuit are integrated through SMA connecter in order to implement the proposed rectenna. Measurement of the proposed rectenna shows an approximate maximum efficiency of 53% at 2 GHz, 31% at 2.5 GHz, and 15.56% at 3.5 GHz.
100 citations
TL;DR: In this article, the authors presented the complete design of a wideband transmit-array (TA) antenna with high gain and high efficiency for D-band applications based on the low-temperature co-fired ceramic technology.
Abstract: This paper presents the complete design of a wideband transmit-array (TA) antenna with high gain and high efficiency for D-band applications based on the low-temperature co-fired ceramic technology. The proposed unit cell is composed of a pair of wideband magnetoelectric dipoles as the receive/transmit elements, together with a substrate-integrated waveguide (SIW) aperture-coupling transmission structure for independent phase adjustability. A 360° phase coverage is obtained by the proposed phasing element, and its phase response curves are nearly parallel within a broad frequency band, which indicates a wideband performance. To verify the design, the fabricated prototype is measured by using a vector network analyzer in a terahertz compact-range anechoic chamber. The measured peak gain is 33.45 dBi at 150 GHz with the aperture efficiency of 44.03%, and the measured 3 dB gain bandwidth is 124–158 GHz (24.29%). The good radiation performance ensures that the proposed SIW aperture-coupling TA antenna is a promising candidate for D-band applications.
100 citations
TL;DR: In this paper, a flexible graphite film was designed and explored to create dipole antennas for radio frequency applications, which achieved a relatively high peak gain of 1.45 dB with comparable return loss, bandwidth, and radiation patterns to an identical copper antenna.
99 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: In this paper, a planar pattern-reconfigurable antenna based on arc dipoles is proposed, which consists of four identical arc dipole and a broadband reconfigurable feeding network, which are printed on the bottom and top layers of the substrate.
Abstract: A simple compact planar pattern-reconfigurable antenna based on arc dipoles is proposed in this letter. The antenna consists of four identical arc dipoles and a broadband reconfigurable feeding network, which are printed on the bottom and top layers of the substrate, respectively. By switching the on/off states of the p-i-n diodes, which are integrated in the reconfigurable feeding network, four different modes with endfire radiation patterns can be obtained in the azimuthal plane. The antenna is simulated, fabricated, and measured. Experimental results indicate that the proposed antenna achieves a bandwidth of 33.6% (2.25–3.16 GHz) for impedance matching better than 10 dB. The measured average gain is 4.11 dBi. Furthermore, the radiation efficiency is up to 60%. The proposed antenna is suitable for WLAN applications in wireless communications.
94 citations
TL;DR: In this paper, a low profile horizontally polarized (HP) omnidirectional metasurface-inspired antenna is presented, which can achieve a 0.06 λ 0 (λ 0 is the free-space wavelength at 5.2 GHz) and a wide operating bandwidth of 16.6%.
Abstract: A low-profile horizontally polarized (HP) omnidirectional metasurface-inspired antenna is presented. To realize HP omnidirectional radiation pattern, the theory of characteristic mode is utilized to facilitate the analysis of three antenna structures. Then, by properly exciting the desired characteristic mode, the antenna with a wide bandwidth and good omnidirectionality, which is based on the modification of the standard patch antenna, is obtained. The simulated results show that the proposed antenna not only can obtain a low profile of 0.06 λ 0 (where λ 0 is the free-space wavelength at 5.2 GHz), but also has a wide operating bandwidth of 16.6%. Finally, the metasurface-inspired antenna is manufactured and the error analysis between the simulated and measured results is also provided. The antenna can be applied to 5G wireless local area network systems.
94 citations
TL;DR: In this article, a single-layer textile MIMO antenna is designed for wearable applications, which utilizes a small ground plane as the main radiator, which is capacitively loaded by two strips along two orthogonal edges.
Abstract: A compact single-layer textile MIMO antenna is designed for wearable applications. The theory of characteristic mode is used to guide the antenna design and analyze its performance. The MIMO antenna utilizes a small ground plane as the main radiator, which is capacitively loaded by two strips along two orthogonal edges. The whole system occupies a volume of 38.1 mm $\times38.1$ mm $\times2$ mm, with each antenna having a dipole-like radiation pattern of linear polarization. Good isolation of above 12 dB is achieved due to the quasi-orthogonal radiations generated by the two antennas, providing pattern and polarization diversities. The envelope correlation coefficient between the antennas is below 0.01. The proposed antenna, fabricated on a flexible felt with a permittivity of 1.2, has a wide bandwidth of 20%. Due to its broadband behavior, the antennas remain well matched at the target band when worn on the body and bended. The loss of the human tissue results in the drop of the antenna gains to 1.6 dBi and 1.2 dBi, respectively, for the two antennas. The proposed antenna is competitive for wearable applications, due to its compact size, single-layer structure, easy integration, robustness, and reasonable on-body antenna gain.
88 citations
TL;DR: In this article, a dual-polarized high-isolation multiple input multiple output (MIMO) antenna array for wideband base-station applications is presented, where the antenna array consisting of four elements is working within the frequency band from 2.4 to 3 GHz and decoupling branches among the elements are introduced to improve the isolation by about 10 dB.
Abstract: A low-profile dual-polarized high-isolation multiple input multiple output (MIMO) antenna array for wideband base-station applications is presented in this paper. The proposed dual-polarized antenna element has the advantage of lower profile ( $0.067\lambda $ ) by utilizing artificial magnetic conductor structure. The antenna array consisting of four elements is working within the frequency band from 2.4 to 3 GHz. Furthermore, decoupling branches among the elements are introduced to improve the isolation by about 10 dB. Both simulation and measured results indicate that the proposed dual-polarized antenna element has a good isolation over 28 dB. Moreover, the beamwidth of the antenna array can be effectively broadened by the adjustment of phase distributions of corresponding artificial material plane. Finally, a larger MIMO system is also investigated, and the simulation and measured results prove that dual-polarized dipole antenna MIMO array has good system performance.
TL;DR: In this paper, a fully integrated wideband 240-GHz transceiver front-end, supporting BPSK modulation scheme, with on-chip antenna is demonstrated in SiGe:C BiCMOS technology with $f_{\text {T}}/f_{ \text {max}}\,\,=$ 300/500 GHz and local backside etching option.
Abstract: In this paper, a fully integrated wideband 240-GHz transceiver front-end, supporting BPSK modulation scheme, with on-chip antenna is demonstrated in SiGe:C BiCMOS technology with $f_{\text {T}}/f_{\text {max}}\,\,=$ 300/500 GHz and local backside etching option. Within the transmitter, the upconversion is provided by fundamental mixing using a modified Gilbert cell mixer driven by a multiplier-by-eight local oscillator (LO) chain. The transmitter achieves a 3-dB RF bandwidth of 35 GHz with a saturated output power of −0.8 dBm. The down converter is equipped with a mixer first architecture. The mixer is designed utilizing a transimpedance amplifier as load for enhanced noise and bandwidth performance. For dc-coupled receiver, two dc offset cancellation loops are implemented within the receiver chain. It achieves a 3-dB RF bandwidth of 55 GHz, minimum single-sideband noise figure (SSB NF) of 13.4 dB, and a gain of 32 dB with 25-dB gain control. A wideband on-chip double-folded dipole antenna and an on-board optical lens are utilized to demonstrate a wireless link achieving 20- and 25-Gb/s data rates at bit error rates (BERs) of $6.3 \times 10^{-6}$ and $2.2\times 10^{-4}$ , respectively, across a distance of 15 cm. The transmitter and receiver consume 375 and 575 mW, respectively, which correspond to power efficiencies of 15 pJ/bit for the transmitter and 23 pJ/bit for the receiver. They occupy a silicon area of 4.3 and 4.5 mm2, respectively.
TL;DR: In this article, a quad-mode end-fire planar phased antenna array with wide scan angle and 1.2 mm clearance is proposed for 5G mobile terminals, which can obtain over 8 GHz of impedance bandwidth.
Abstract: In this paper, a quad-mode endfire planar phased antenna array with wide scan angle and 1.2 mm clearance is proposed for 5G mobile terminals. The proposed antenna can obtain over 8 GHz of impedance bandwidth. In this paper, it is suggested to efficiently combine a multimode array element with different radiation patterns for each mode into a phased antenna array. In the array, similar and wide embedded radiation patterns are obtained for the all four modes. Furthermore, a coaxial to differential stripline transition is designed in this paper. The differential feeding structure is very compact and utilizes only MMPX connector and vias. The total scan pattern and coverage efficiency of the measured and simulated phased array antenna are calculated in the range from 25 to 33 GHz, and good agreement between measured and simulated results is observed. The mean coverage efficiency along the frequency range is very similar, but minor difference in variance of coverage efficiency is observed in the measurements. The coverage efficiency of around 50% for the threshold gain of 5 dBi is achieved in the chosen frequency range.
TL;DR: In this paper, a low-profile wideband circularly polarized (CP) crossed-dipole antenna that has both wide axial-ratio beamwidth (ARBW) and half-power beam width (HPBW) is presented.
Abstract: A low-profile wideband circularly polarized (CP) crossed-dipole antenna that has both wide axial-ratio beamwidth (ARBW) and half-power beamwidth (HPBW) is presented in this paper. The crossed dipoles are composed of four trapezoidal patch arms, and they are fed by a pair of vacant-quarter printed rings to generate CP radiation. Four identical parasitic elements that consist of a horizontal triangle patch and a vertical metallic plate are symmetrically intervened between the crossed dipoles and the ground plane. It has been found that the parasitic elements can effectively decrease the antenna profile, increase the operating bandwidth, and simultaneously enhance the ARBW as well as the HPBW. A prototype was fabricated and measured to verify the design. The measured results show that the prototype has a low profile of $0.1\lambda _{0}$ , a −10 dB impedance bandwidth of 78.3% and a 3 dB AR bandwidth of 63.4%. Moreover, a 3 dB ARBW of more than 120° and an HPBW of more than 110° are achieved simultaneously within a wide passband of 50.7%.
TL;DR: In this paper, a miniaturized circularly polarized (CP) implantable antenna is designed at 915 ISM band for far-field wireless power transmission, which has the smallest size and maintains good radiation performance, compared with previous CP implantable antennas.
Abstract: A wireless power link with circular polarization is studied in this letter for far-field wireless power transmission. First, a miniaturized circularly polarized (CP) implantable antenna is designed at 915 ISM band. The proposed antenna features a good miniaturization with the dimensions of 11 × 11 × 1.27 mm3 by employing the stub loading and capacitive coupling among the stubs. It has the smallest size and maintains good radiation performance, compared with previous CP implantable antennas. The simulated impedance bandwidth covers from 889 to 924 MHz for | S 11| less than −10 dB, and the axial-ratio (AR) bandwidth (AR < 3 dB) is from 901 to 912 MHz. The results show that the antenna is suitable for far-field wireless power transmission. The proposed wireless power link achieves higher converted dc power compared to previous similar letter.
TL;DR: In this article, a dual-polarized broadband antenna array for base stations is proposed for the purpose of low profile, low profile and ease of mass production, and printed dipoles are adopted as the dual-Polarized antenna element.
Abstract: A compact $\pm \text{45}^{\circ }$ dual-polarized broadband antenna array is proposed in this letter for base stations. For the sake of structural simplicity, low profile, and ease of mass production, printed dipoles are adopted as the dual-polarized antenna element. To achieve the broadband performance, radiators are designed to be spline-edged bowties, and they are fed by tapered transmission lines. Moreover, to improve the symmetry and stability of the radiation pattern, the Pawsey stub baluns are used to balance the antenna structure. Finally, an eight-element antenna array prototype backed by a folded reflector is fabricated and measured. The compact antenna array has a broad bandwidth of 68% (1.427–2.9 GHz) with a voltage standing-wave ratio less than 1.5 and stable radiation properties to provide international mobile telecommunication services over 2G/3G/LTE systems and L- and S -bands released recently.
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.
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: In this paper, an extremely broadband circularly polarized (CP) antenna is presented, which consists of a crossed bowtie dipole loaded with four unequal parasitic cross slots, four parasitic bowtie patches, and four parasitic rectangular strips.
Abstract: An extremely broadband circularly polarized (CP) antenna is presented. The proposed antenna consists of a crossed bowtie dipole loaded with four unequal parasitic cross slots, four parasitic bowtie patches, and four parasitic rectangular strips. The cross slots can generate a CP mode due to the sequential phases of the crossed bowtie dipole. The parasitic bowtie patches are gap-coupled with two arms of the crossed bowtie dipole, and they are sequentially rotated along diagonals to generate an additional CP mode. The parasitic strips also generate one CP mode due to the sequentially rotated configuration parallel to the crossed bowtie dipole. By properly combining with two CP modes of the crossed bowtie dipole, broadband CP operation is achieved. The experimental and simulated results are in agreement, and the measured results show that the proposed antenna exhibits a very wide impedance bandwidth of 93.1% (2.21–6.06 GHz) and an excellent axial-ratio bandwidth of 90.9% (2.2–6.4 GHz). In addition, the proposed antenna produces a right-hand circular polarization with a peak gain of 8.6 dBi.
TL;DR: In this paper, a wideband magnetoelectric (ME) dipole antenna with wide beamwidth both in the E-plane and H-plane is investigated, which is a differential one.
Abstract: In this paper, a wideband magnetoelectric (ME) dipole antenna with wide beamwidth both in the E-plane and H-plane is investigated The proposed antenna, which is a differential one, has a simple structure and can realize wide beamwidth in the E-plane and H-plane in whole operating bandwidth This antenna is easy to manufacture and low cost The antenna consists of a pair of $\Gamma$ -shaped metal plates, a $\Gamma$ -shaped fed line, and six metal columns The $\Gamma$ -shaped metal plates and metal columns change the current distribution which changes the radiation performance of the proposed antenna Some parameters, which effect on the performances of the antenna, are studied The proposed antenna achieves the impedance bandwidth (≤−10 dB) of about 811% (33–78 GHz) The half-power beamwidth (HPBW) of the proposed antenna is obviously broadened The HPBW is 215° in the E-plane and 186° in the H-plane at 55 GHz Besides, the cross polarization of the antenna is very low The antenna is fabricated and measured to verify the design The measured results are in good agreements with the simulated one Good radiation characteristics of the new ME dipole antenna have been obtained in the whole frequency band
TL;DR: In this article, a low radar cross section (RCS) antenna designed with band-notched absorber is described, where a dual-polarization absorber with relative bandwidth more than 80% is designed using loaded resistors.
Abstract: A low radar cross section (RCS) antenna designed with band-notched absorber is described. First, a dual-polarization absorber with relative bandwidth more than 80% is designed using loaded resistors. Pairs of circular slot resonators and metal strip array resonators are introduced in the absorber to realize a notch band with full reflectance in the vertical polarization, while a wide absorption band in the horizontal polarization is maintained. The proposed band-notched absorber is thus realized. Within the notch band, the absorber can be served as a metal ground for antenna; while a great RCS reduction is obtained out of the notch band and in the horizontal polarization band. Then, a dipole antenna rigorously designed is mounted above the band-notched absorber, whose operating frequency is exactly in accordance with that of the notch band. The proposed low RCS antenna is established based on assembling the dipole antenna and the band-notched absorber together. The measured results demonstrate that the proposed antenna has fairly good radiation patterns. Added to that, more than 10 dB RCS reduction in two polarizations is realized simultaneously compared with that one of a conventional dipole antenna.
TL;DR: In this article, a space-time varying metamaterial cloak is proposed to enhance the performance of radio-frequency communication systems, reducing the in-band captured noise or interfering signals.
Abstract: Conventionally, antennas are reciprocal devices, exhibiting the same properties in transmission and in reception. In order to break antenna reciprocity, in this letter, we exploit the properties of space-time varying metamaterials, whose dielectric properties are modulated in both space and time. We propose to surround the antenna by a space-time varying cloak that imparts a momentum bias to the electromagnetic field propagating through it. The propagating wave interacts with the space-time modulation only in one direction, breaking time-reversal symmetry and, thus, the reciprocity of the system. Here, we show that a properly designed space-time varying metamaterial cloak can be used to significantly change the realized gain exhibited by an antenna in its transmission and reception mode. Since the proposed concept is based on weak coupling between propagating modes, electrically long propagation distance in the cloak is required, increasing the overall dimension of the system. However, the cloak thickness can be controlled by modifying the modulation parameters. The proposed concept may enhance the performance of radio-frequency communication systems, reducing the in-band captured noise or interfering signals.
TL;DR: In this article, an electrically actuated reconfigurable liquid-metal dipole antenna is presented using electrocapillary actuation, a 5 VDC signal can actuate the liquid metal Galinstan into five discrete states with varying polarizations and null directions.
Abstract: An electrically actuated reconfigurable liquid-metal dipole antenna is presented. Using electrocapillary actuation, a 5 VDC signal can actuate the liquid metal Galinstan into five discrete states with varying polarizations and null directions. Local surface-energy wells built into the polyimide fixture encasing the fluids enable metastable locking of the Galinstan, eliminating the need for a continuous dc bias voltage to maintain each state.
Abstract: A novel circularly polarized (CP) complementary source antenna with endfire radiation is proposed in Ka-band. With the existence of two antipodal notches etched at the edges of the two broad walls of an open-ended substrate-integrated waveguide, two orthogonal electric field components radiated from the equivalent magnetic current, and the electric currents separately can be excited simultaneously. The magnitude and phase differences between the two filed components can be controlled effectively by properly tuning the dimensions of the notches. The operating mechanism and the design procedure of the antenna are analyzed in detail. Wide −10 dB impedance and 3 dB axial ratio bandwidths of 64% and 51%, a gain varying from 3.1 to 6.4 dBic, and the symmetrical radiation pattern are obtained. In order to further increase the gain and front-to-back ratio (FTBR) of the antenna, a dielectric rod structure is then integrated with the antenna. An overlapped operating bandwidth of 41%, an improved gain up to 12 dBic and the stable radiation pattern with an FTBR close to 20 dB are verified by a fabricated prototype. The antenna presented in this paper provides a new mean to design the wideband endfire CP antenna with a simple configuration, which would be attractive for future millimeter-wave wireless systems.
TL;DR: In this paper, a wideband miniaturized circularly polarized implantable antenna operating at 915 MHz Industrial, Scientific, and Medical (ISM) band is presented and experimentally verified.
Abstract: A wideband miniaturized circularly polarized implantable antenna operating at 915 MHz Industrial, Scientific, and Medical (ISM) band is presented and experimentally verified in this letter. Compared with previous work, the patch antenna with the dimensions of $\pi \times ({\text{4.7}})^{2}\times {\text{1.27}}\ {\text{mm}}^{3}$ features a better size reduction. The miniaturization of the proposed antenna is well implemented by cutting several kinds of slots to extend the current path. Moreover, a shorting pin is introduced to lower the resonant frequency and prompt circular polarization (CP) purity. Specific absorption rate is also calculated to consider whether it can meet the safety standards. The simulated results in one-layer cubic skin phantom demonstrates that the impedance bandwidth (BW) of 12.2% and the 3 dB axial-ratio BW of 19.7% can be obtained. Finally, the antenna is measured in the skin-mimicking solution, and the measured BW achieves about 17.5%, which generally agrees with the simulated.
TL;DR: In this paper, a dual-band dipole array antenna consisting of two parallel $1 \times 4$ subarrays for use in base stations operating in the digital cellular system (DCS) and wideband code division multiple access (WCDMA) bands is presented.
Abstract: A novel miniaturized dual-band dipole array antenna consisting of two parallel $1 \times 4$ subarrays for use in base stations operating in the digital cellular system (DCS) and wideband code division multiple access (WCDMA) bands is presented. Size miniaturization is realized by utilizing band notch dipoles (BNDs) as array elements and artificial magnetic conductors as reflectors for reductions in width and profile height of the array antenna, respectively. Using the BNDs of high radiation suppression at desired notch frequencies, the radiation from DCS subarray is suppressed in the WCDMA band and vice versa. High isolation between the subarrays, therefore, is achieved while reducing the subarray separation. In addition, a dual four-way unequal power divider is designed for beam pattern synthesis. The measured results show that realized gains of 12.1–12.6 and 12.4–13.1 dBi, respectively, within the DCS and WCDMA bands, as well as the first null depth and sidelobe level, respectively, of lower than −20 and −16 dB, are achieved simultaneously, indicating that the proposed array antenna is suitable for potential base station applications.
TL;DR: In this paper, a 2D scanning magnetoelectric (ME) dipole antenna array fed by printed ridge gap waveguide (PRGW) matrix is proposed to achieve a bandwidth wider than 20% at 30 GHz and stable gain of 6.5 ± 0.8 dB over the operating frequency bandwidth.
Abstract: In this paper, a 2-D scanning magnetoelectric (ME) dipole antenna array fed by printed ridge gap waveguide (PRGW) Butler matrix is proposed. The ME dipole antenna is designed to achieve a bandwidth wider than 20% at 30 GHz and stable gain of 6.5 ± 0.8 dB over the operating frequency bandwidth. A $4\times 4$ planar PRGW Butler matrix is designed and constructed using a four PRGW hybrid couplers having a wide bandwidth performance. The overall performance of the Butler matrix exhibits about 5° phase error over the operating frequency bandwidth. The integration of ME dipole antennas with the designed Butler matrix results in four fixed beams, one in each quadrant at an elevation angle of 35° from the broadside to the array axis. The proposed passive beam switching network (BSN) has a wide bandwidth of 20% with radiation efficiency higher than 84% over the operating bandwidth. The proposed BSN shows a stable radiation pattern with a stable gain of 10.3±0.2 dB, where the sidelobe level is less than −15 dB over the whole operating frequency band. The fabricated prototype of the proposed BSN is tested, where the measured and simulated results show an excellent agreement.
TL;DR: In this paper, a novel ultra-wide-band tightly coupled dipole reflectarray (TCDR) antenna is presented, which consists of a wideband feed and a wide-band reflecting surface.
Abstract: A novel ultra-wide-band tightly coupled dipole reflectarray (TCDR) antenna is presented in this paper. This reflectarray antenna consists of a wideband feed and a wideband reflecting surface. The feed is a log-periodic dipole array antenna. The reflecting surface consists of $26 \times 11$ unit cells. Each cell is composed of a tightly coupled dipole and a delay line. The minimum distance between adjacent cells is 8 mm, which is about 1/10 wavelength at the lowest operating frequency. By combining the advantages of reflectarray antennas and those of tightly coupled array antennas, the proposed TCDR antenna achieves ultra-wide bandwidth with reduced complexity and fabrication cost. A method to minimize the phase errors of the wideband reflectarray is also developed and the concept of equivalent distance delay is introduced to design the unit cell elements. To verify the design concept, a prototype operating from 3.4 to 10.6 GHz is simulated and fabricated. Good agreement between simulated and measured results is observed. Within the designed frequency band, the radiation pattern of the TCDR antenna is stable and the main beam of the antenna is not distorted or split. The side lobe levels of the radiation patterns are below −11.7 dB in the entire operating band. It is the first time a tightly coupled reflectarray is reported.
TL;DR: An adaptive beamforming algorithm using a dual-polarized GPS antenna array for mitigation of interference signals with various polarizations is proposed and the performance of the proposed method in terms of the signal-to-interference-plus-noise power ratio (SINR) is noticeably superior to that of previous methods under a representative interference scenario.
TL;DR: Reconfigurable antenna systems represent novel classes of frequency, pattern, polarization, and beam-direction reconfigurable systems realized by the innovative combinations of radiating structures and circuit components.
Abstract: Future fifth generation (5G) wireless platforms will require reconfigurable antenna systems to meet their performance requirements in compact, light-weight, and cost-effective packages. Recent advances in reconfigurable radiating and receiving structures have been enabled by a variety of innovative technology solutions. Examples of reconfigurable partially reflective surface antennas, reconfigurable filtennas, reconfigurable Huygens dipole antennas, and reconfigurable feeding network-enabled antennas are presented and discussed. They represent novel classes of frequency, pattern, polarization, and beam-direction reconfigurable systems realized by the innovative combinations of radiating structures and circuit components.