Showing papers on "Patch antenna published in 2011"
TL;DR: In this article, a triple-frequency microstrip-fed planar monopole antenna for multiband operation is proposed and investigated, which has a small overall size of 20 × 30 mm2, and operates over the frequency ranges 2.14-2.52 GHz, 2.82-3.74 GHz, and 5.15-6.02 GHz suitable for WLAN 2.4/5.8 GHz and WiMAX 3.5/5 GHz applications.
Abstract: A novel triple-frequency microstrip-fed planar monopole antenna for multiband operation is proposed and investigated. Defected ground structure (DGS) is used in this antenna, which has a rectangular patch with dual inverted L-shaped strips and is fed by a cross-shaped stripline, for achieving additional resonances and bandwidth enhancements. The designed antenna has a small overall size of 20 × 30 mm2, and operates over the frequency ranges, 2.14-2.52 GHz, 2.82-3.74 GHz, and 5.15-6.02 GHz suitable for WLAN 2.4/5.2/5.8 GHz and WiMAX 3.5/5.5 GHz applications. There is good agreement between the measured and simulated results. Experimental results show that the antenna gives monopole-like radiation patterns and good antenna gains over the operating bands. In addition, effects of both the length of the protrudent strips and the dimensions of the DGS for this design on the electromagnetic performance are examined and discussed in detail.
270 citations
TL;DR: In this article, a miniaturized multifrequency antenna is proposed, which consists of a circular ring, a Y-shape-like strip, and a defected ground plane.
Abstract: A miniaturized multifrequency antenna is proposed. The proposed antenna can generate three separate impedance bandwidths to cover all the 2.4/5.2/5.8-GHz WLAN operating bands and the 2.5/3.5/5.5-GHz WiMAX bands. The proposed microstrip-fed antenna mainly consists of a circular ring, a Y-shape-like strip, and a defected ground plane. By adding a Y-shape-like strip in the circular ring, the antenna excites two resonant modes and is with miniaturization structure. Because of the introduction of the cambered ground plane with an isosceles triangle-defect, the third wide band with better impedance matching is obtained. A prototype is experimentally tested, and the measured results show good radiation patterns and enough gains across the operation bands.
251 citations
TL;DR: In this article, a compact microstrip line-fed ultrawideband (UWB) tapered-shape slot antenna is presented, which is fabricated onto an inexpensive FR4 substrate with an overall dimension of 22 × 24 mm2.
Abstract: A compact microstrip line-fed ultrawideband (UWB) tapered-shape slot antenna is presented. The proposed antenna comprises a tapered-shape slot and rectangular tuning stub. The antenna is fabricated onto an inexpensive FR4 substrate with an overall dimension of 22 × 24 mm2. The experiment shows that the proposed antenna achieves good impedance matching constant gain, stable radiation patterns over an operating bandwidth of 3-11.2 GHz (115.5%) that covers the entire UWB. The nearly stable radiation pattern with a maximum gain of 5.4 dBi makes the proposed antenna suitable for being used in UWB communication applications.
239 citations
TL;DR: In this paper, the authors proposed a multi-beam leaky-wave pillbox antenna based on three main parts: feeding part (integrated horns), quasi-optical system and radiating part.
Abstract: This work proposes a novel multi-beam leaky-wave pillbox antenna. The antenna system is based on three main parts: feeding part (integrated horns), quasi-optical system and radiating part. The radiating and input parts are placed in two different stacked substrates connected by an optimized quasi-optical system. In contrast to conventional pillbox antennas, the quasi-optical system is made by a pin-made integrated parabola and several coupling slots whose sizes and positions are used to efficiently transfer the energy coming from the input part to the radiating part. The latter consists of a printed leaky-wave antenna, namely an array of slots etched on the uppermost metal layer. Seven pin-made integrated horns are placed in the focal plane of the integrated parabola to radiate seven beams in the far field. Each part of the antenna structure can be optimized independently, thus facilitating and speeding up the complete antenna design. The antenna concept has been validated by measurements (around 24 GHz) showing a scanning capability over ±30° in azimuth and more than 20° in elevation thanks to the frequency scanning behavior of the leaky-wave radiating part. The proposed antenna is well suited to low-cost printed circuit board fabrication process, and its low profile and compactness make it a very promising solution for applications in the millimeter-wave range.
231 citations
TL;DR: In this paper, four compact asymmetric-slit microstrip antennas were proposed and studied for circular polarization by cutting asymmetrical slits in diagonal directions onto the square microstrip patches, the single coaxial feed microstrip patch antennas were realized for circularly polarized radiation with compact antenna size.
Abstract: Four compact asymmetric-slit microstrip antennas are proposed and studied for circular polarization. By cutting asymmetrical slits in diagonal directions onto the square microstrip patches, the single coaxial-feed microstrip patch antennas are realized for circularly polarized radiation with compact antenna size. The performances of the proposed antennas with several asymmetric-slit shapes onto the patch radiators are compared. The measured 10-dB return loss and 3-dB axial-ratio bandwidths of the antenna prototype are around 2.5% and 0.5%, respectively. The proposed asymmetric-slit configurations are useful for compact circularly polarized microstrip patch antennas and array design.
208 citations
TL;DR: In this article, a metamaterial-inspired low-profile patch antenna is proposed and studied for circularly-polarized (CP) radiation, which is realized by exciting two orthogonally polarized modes simultaneously which are located in the left-handed region.
Abstract: A metamaterial-inspired low-profile patch antenna is proposed and studied for circularly-polarized (CP) radiation. The present antenna, which has a single-fed configuration, is loaded with the composite right/left-handed (CRLH) mushroom-like structures and a reactive impedance surface (RIS) for miniaturization purpose. The CP radiation is realized by exciting two orthogonally-polarized modes simultaneously which are located in the left-handed (LH) region. The detailed antenna radiation characteristics are examined and illustrated with both simulated and experimental results. The CP performance can be controlled in several different ways. This antenna exhibits an overall size of 0.177λ0 × 0.181λ0 × 0.025λ0 at 2.58 GHz and a radiation efficiency around 72%. Finally, based on the proposed CP patch antenna, a compact dual-band dual linearly-polarized patch antenna has also been designed and fabricated. Promising experimental results are observed.
195 citations
TL;DR: In this paper, two microstrip square open-loop resonators, a coupled line, and a Γ-shaped antenna are used and integrated to be a filter-antenna.
Abstract: Design, fabrication, and measurement of a new compact filter-antenna for modern wireless communication systems are presented in this letter. Two microstrip square open-loop resonators, a coupled line, and a Γ-shaped antenna are used and integrated to be a filter-antenna. The Γ-shaped antenna is excited by a coupled line that is treated as the admittance inverter in filter design. The Γ-shaped antenna performs not only a radiator, but also the last resonator of the bandpass filter. Therefore, near-zero transition loss is achieved between the filter and the antenna. The design procedure follows the circuit approach-synthesis of bandpass filters. Measured results show that the filter-antenna achieves an impedance bandwidth of 16.3% (over 2.26-2.66 GHz) at a reflection coefficient |S11 | <; - 10 dB and has a gain of 2.41 dBi.
192 citations
TL;DR: In this paper, a horizontally meandered strip (HMS) feed technique is proposed to achieve good impedance matching and symmetrical broadside radiation patterns for a single-fed broadband circularly polarized stacked patch antenna, which is suitable for universal ultra-high frequency (UHF) RF identification (RFID) applications.
Abstract: In this paper, a horizontally meandered strip (HMS) feed technique is proposed to achieve good impedance matching and symmetrical broadside radiation patterns for a single-fed broadband circularly polarized stacked patch antenna, which is suitable for universal ultrahigh frequency (UHF) RF identification (RFID) applications. The antenna is composed of two corner truncated patches and an HMS, all of which are printed on the upper side of the FR4 substrates. One end of the HMS is connected to the main patch by a probe, while the other end is connected to an SMA connector. Simulation results are compared with the measurements, and a good agreement is obtained. The measurements show that the antenna has an impedance bandwidth (VSWR <; 1.5) of about 25.8% (758-983 MHz), a 3-dB axial ratio (AR) bandwidth of about 13.5% (838-959 MHz), and a gain level of about 8.6 dBic or larger within the 3-dB AR bandwidth. Therefore, the proposed antenna can be a good candidate for universal UHF RFID readers operating at the UHF band of 840-955 MHz. In addition, a parametric study and a design guideline of the proposed antenna are presented to provide the engineers with information for designing, modifying, and optimizing such an antenna. At last, the proposed antenna is validated in RFID system applications.
184 citations
TL;DR: In this article, a fractal monopole antenna is proposed for the application in the UWB frequency range, which is designed by the combination of two fractal geometries.
Abstract: A fractal monopole antenna is proposed for the application in the UWB frequency range, which is designed by the combination of two fractal geometries. The first iterations of Giusepe Peano fractal are applied on the edges of a square patch, and a Sierpinski Carpet fractal is formed on its surface. The feed circuit is a microstrip line with a matching section over a semi-elliptical ground plane. The presented antenna has an omnidirectional radiation pattern, a good gain, and high efficiency. The fabrication and measurement data attest to the satisfaction of the design specifications.
183 citations
TL;DR: In this paper, a 2.45 GHz rectifying antenna (rectenna) using a compact dual circularly polarized (DCP) patch antenna with an RF-dc power conversion part is presented.
Abstract: A 2.45-GHz rectifying antenna (rectenna) using a compact dual circularly polarized (DCP) patch antenna with an RF-dc power conversion part is presented. The DCP antenna is coupled to a microstrip line by an aperture in the ground plane and includes a bandpass filter for harmonic rejections. It exhibits a measured bandwidth of 2100 MHz (10 dB return loss) and a 705-MHz CP bandwidth (3 dB axial ratio). The maximum efficiency and dc voltage are respectively equal to 63% and 2.82 V over a resistive load of 1600 Ω for a power density of 0.525 mW/cm2.
178 citations
TL;DR: In this paper, a U-shape radiating patch is excited by a T-shape resonator through an inset coupling structure, which acts as a radiator as well as the last stage of the filter.
Abstract: Design, fabrication, and measurement of a compact filtering microstrip antenna with second-order quasi-elliptic broadside antenna gain response are presented. A U-shape radiating patch is excited by a T-shape resonator through an inset coupling structure. The U-shape patch acts as a radiator as well as the last stage of the filter, and the inset coupling structure can be treated as the admittance inverter in filter design. The design procedure follows the circuit approach-synthesis of bandpass filters. The broadside gain of the filtering antenna has two poles in passband and two broadside radiation nulls (zeros) at the band edges for improving selectivity. Compared to the conventional inset-fed microstrip antenna, with a little extra circuit area, the proposed filtering antenna has a flatter passband response, better frequency skirt selectivity, and almost twice wider bandwidth. The measurement result shows a good agreement with the simulations.
TL;DR: In this article, a three-dimensional broadband, low-loss, dual-polarization, and high-directivity lens antenna using gradient index (GRIN) metamaterials, which is composed of multi-layer microstrip square-ring arrays.
Abstract: We present the theoretical modeling and prototype demonstration of a three-dimensional broadband, low-loss, dual-polarization, and high-directivity lens antenna using gradient index (GRIN) metamaterials, which is composed of multi-layer microstrip square-ring arrays. The elements of metamaterials, closed square-ring units of variable sizes, are distributed on the planar substrate to satisfy the radial gradient index function and the axial impedance matching layer configuration of the lens. The gradient-index metamaterials are designed to transform the spherical wave-front into the planar wave-front and to minimize the reflection loss. A prototype lens antenna, which consists of a metal conical horn and the gradient-index lens, are simulated, constructed, and measured. The resemblance of simulation and measurement results shows that the prototype lens antenna maintains low return loss and high directivity on the whole X-band (from 8 GHz to 12 GHz). Compared to the traditional horn antenna, the metamaterial...
TL;DR: In this paper, a broadband circularly polarized patch antenna using an artificial ground (AG) structure with rectangular unit cells as a reflector is presented. And the results show a 10 dB return loss of 48.6% and a 3 dB axial ratio bandwidth of 20.4%.
Abstract: This paper presents a broadband circularly polarized patch antenna using an artificial ground (AG) structure with rectangular unit cells as a reflector. The AG structure changes the reflection phase in accordance with the polarization state of the incident wave. By properly combining the transmitted wave from the antenna and the reflected wave from the AG structure, broadband circular polarization can be obtained. The AG structure and the antenna are simulated using a full-wave solver and the results show a 10 dB return loss bandwidth of 48.6% and a 3 dB axial ratio bandwidth of 20.4%. The measured results are in good agreement with the simulated results. The radiation characteristics of the antenna are almost the same as those for an antenna with a PEC reflector.
Patent•
15 Sep 2011TL;DR: An electrically small dual-band planar tunable UHF/L-band antenna was proposed in this article, which includes a combination of a semi-spiral antenna for UHF frequencies and a microstrip patch antenna for the L-band frequencies.
Abstract: An electrically small dual-band planar tunable UHF/L-Band antenna In one example, the dual-band antenna includes a combination of a semi-spiral antenna for the UHF frequencies and a microstrip patch antenna for the L-band frequencies
TL;DR: Study of possibilities to construct a flexible, lightweight and mechanically robust textile antenna for dual-band satellite use: Iridium and GPS and the developed antenna solution allows integration into clothing.
Abstract: Integrating antennas into fabrics is a potential way for facilitating many applications, such as health monitoring of patients, fire-fighting, rescue work, and space and military personal communications. This paper studies possibilities to construct a flexible, lightweight and mechanically robust textile antenna for dual-band satellite use: Iridium and GPS. Different textile materials were characterized and the most promising materials were used to design, construct, and test a rectangular patch antenna. The gain and axial ratio for both bands is compliant with specifications and relatively stable under most bending conditions. The developed antenna solution allows integration into clothing.
TL;DR: In this paper, a simple, low-cost, and compact printed dual-band fork-shaped monopole antenna for Bluetooth and ultrawideband (UWB) applications is proposed.
Abstract: A simple, low-cost, and compact printed dual-band fork-shaped monopole antenna for Bluetooth and ultrawideband (UWB) applications is proposed. Dual-band operation covering 2.4-2.484 GHz (Bluetooth) and 3.1-10.6 GHz (UWB) frequency bands are obtained by using a fork-shaped radiating patch and a rectangular ground patch. The proposed antenna is fed by a 50-Ω microstrip line and fabricated on a low-cost FR4 substrate having dimensions 42 (Lsub) × 24 (Wsub) × 1.6 (H) mm3. The antenna structure is fabricated and tested. Measured S11 is ≤ -10 dB over 2.3-2.5 and 3.1-12 GHz. The antenna shows acceptable gain flatness with nearly omnidirectional radiation patterns over both Bluetooth and UWB bands.
TL;DR: In this paper, a 3 × 2 microstrip antenna array is designed at a center frequency of 5 GHz with 3% fractional bandwidth and Chebyshev 0.3dB equal-ripple broadside antenna gain response.
Abstract: A new filtering microstrip antenna array is presented. The antenna elements, together with the very compact feeding network, function as a third-order bandpass filter. The feeding network, which consists of one power divider and two baluns, provides the first two stages, and the microstrip antenna elements provide the last stage in the filter design. The equivalent lumped circuit model is analyzed, and the detail synthesis procedure is presented. A third-order filtering 2 × 2 microstrip antenna array is designed at a center frequency of 5 GHz with 3% fractional bandwidth and Chebyshev 0.3-dB equal-ripple broadside antenna gain response. The results from circuit model, full-wave simulation, and measurements agree well. Compared to the conventional patch antenna array, the proposed filtering microstrip antenna array successfully suppresses the unwanted signals in out-of-band, preserves good selectivity at band edges, and retains the flatness of the passband broadside antenna gain response.
TL;DR: In this article, a single-feed circularly polarized (CP) patch antenna at L-band was designed and built using the recently developed U-slot loaded patch technique, which achieved a reasonable axial-ratio bandwidth.
Abstract: A single-feed circularly polarized (CP) patch antenna at L-band is designed and built using the recently developed U-slot loaded patch technique. With the presence of the U-slot, the antenna fabricated on a high-dielectric-constant (er = 10.02) substrate achieves a reasonable axial-ratio bandwidth. At the operating frequency of 1.575 GHz, the size of the patch is 0.13λo × 0.13λo, while the ground size is 0.315λo × 0.315λo and the thickness of the substrate is 0.05λo. The measured gain is 4.5 dBi, and axial-ratio bandwidth is 3.2%.
Patent•
19 Apr 2011
TL;DR: The dual-polarized microstrip antenna of multi-layer radiation structure is designed in a relatively small volume, which effectively saves the cost of antenna installation and maintenance, and is widely applied in the fields of mobile communication and internet technology as discussed by the authors.
Abstract: A dual-polarized microstrip antenna includes: at least one metal radiating patch, i.e. a first metal radiating patch; at least one ground metal layer whereon excitation micro-slots are etched; at least one dielectric layer, i.e. a first dielectric layer it is preferred that the dielectric layer is a resonant dielectric layer such as a resonant dielectric layer of air or other layers of optimization resonant materials; at least one set of bipolar excitation microstrip lines; the dielectric layer is between the first metal radiating patch and the ground metal layer. The dual-polarized microstrip antenna of multi-layer radiation structure is designed in a relatively small volume, which effectively saves the cost of antenna installation and maintenance, and is widely applied in the fields of mobile communication and internet technology.
Patent•
11 Aug 2011
TL;DR: In this article, a wireless device having an improved antenna system is disclosed, comprising one or more antenna, preferably circularly polarized antenna, for transmitting or receiving a signal, and a floating ground planes, wherein the floating ground plane preferably is electrically isolated from and in sufficient proximity to the antenna so that it is inductively coupled to the antennas.
Abstract: A wireless device having an improved antenna system is disclosed comprising one or more antenna, preferably circularly polarized antenna, for transmitting or receiving a signal, and one or more floating ground planes, wherein the floating ground plane preferably is electrically isolated from and in sufficient proximity to the antenna so that it is inductively coupled to the antenna. The floating ground plane may comprise one or more of a strip, band, foil, plate, block, wire mesh, sheet or coating of conductive material and, for example, may be a relatively thin copper strip, band, foil or coating. The circularly polarized antenna, preferably comprises a flat planar shaped radiating element sized and configured to resonate at a predetermined, desired frequency, frequencies or band of frequencies, and a flat planar shaped antenna ground, both radiating element and antenna ground formed on the same printed circuit board. The radiating element is electrically isolated from the antenna ground but sufficiently close to resonate at the desired frequencies. Preferably the floating ground plane is larger than or more massive than the antenna ground, and preferably larger than or more massive than the radiating element. In a further embodiment the wireless device comprises a housing for interfacing with a user, the housing comprising a conductive contact exposed to the exterior of the housing and configured to be contacted by a user, wherein the conductive contact is electrically connected to the floating ground plane, preferably so that the user is coupled to the antenna and becomes part of the antenna system. The floating ground plane may also preferably be configured to substantially cover or overlap the antenna, and may also be configured to distribute and propagate the electromagnetic signals away from the head of the user.
TL;DR: In this article, a shape shifting antenna that changes electrical length and frequency in a controlled and rapid response to pressure is described, which is composed of a liquid metal alloy (eutectic gallium indium) injected into microfluidic channels that feature rows of posts that separate adjacent segments of the metal.
Abstract: This letter describes the fabrication and characterization of a shape shifting antenna that changes electrical length and therefore, frequency, in a controlled and rapid response to pressure. The antenna is composed of a liquid metal alloy (eutectic gallium indium) injected into microfluidic channels that feature rows of posts that separate adjacent segments of the metal. The initial shape of the antenna is stabilized mechanically by a thin oxide skin that forms on the liquid metal. Rupturing the skin merges distinct segments of the metal, which rapidly changes the length, and therefore frequency, of the antenna. A high speed camera elucidates the mechanism of merging and simulations model accurately the spectral properties of the antennas.
TL;DR: In this article, a printed monopole antenna for ultra wideband applications is proposed, which consists of a square radiating patch with an inverted T-shaped slot and a ground plane with inverted t-shaped conductor-backed plane, which provides a wide usable fractional bandwidth of more than 130% (2.91-14.1 GHz).
Abstract: We present a novel printed monopole antenna for ultra wideband applications. The proposed antenna consists of a square radiating patch with an inverted T-shaped slot and a ground plane with an inverted T-shaped conductor-backed plane, which provides a wide usable fractional bandwidth of more than 130% (2.91-14.1 GHz). By cutting a modified inverted T-shaped slot with variable dimensions on the radiating patch and also by inserting an inverted T-shaped conductor-backed plane, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band. The designed antenna has a small size of 12 × 18 mm2 . Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.
TL;DR: In this article, the general method of using U-slots to design dual-and triple-band patch antennas is described, which is suitable when the frequency ratios of the adjacent bands are small, usually less than 1.5.
Abstract: The general method of using U-slots to design dual- and triple-band patch antennas is described. In this approach, one starts with a broadband patch antenna, which can consist of one or more patches. When a U-slot is cut in one of the patches, a notch is introduced into the matching band, and the antenna becomes a dual-band antenna. If another U-slot is cut in the same patch or in another patch, a triple-band antenna results. This method is applied to the L-probe-fed patch, the M-probe-fed patch, as well as the coaxially fed and aperture-coupled stacked patches. It is found that the patterns and gains of the dual-and triple-band antennas are similar to those of the original broadband antenna. Because the band notches introduced by the U-slots occur within the bandwidth of the antenna without slots, this method is suitable when the frequency ratios of the adjacent bands are small, usually less than 1.5.
TL;DR: In this paper, two planar antennas operating in the unlicensed 60 GHz frequency band are presented based on the physical layer specifications of IEEE 802.15.3c and ECMA 387 standards for different classes of wireless applications.
Abstract: Two compact planar antennas operating in the unlicensed 60 GHz frequency band are presented based on the physical layer specifications of IEEE 802.15.3c and ECMA 387 standards for different classes of wireless applications. Each antenna is an array of 2 × 2 microstrip antennas covering at least two channels of the 60 GHz spectrum. The first antenna is optimized to achieve the highest gain, while the second antenna is optimized to give the largest beamwidth. The maximum measured radiation gain of the first antenna is 13.2 dBi. The measured beamwidth and gain of the second antenna are 76° and 10.3 dBi, respectively. The areas of these two antenna are only 0.25 and 0.16 cm2. The variation of radiation gain of each antenna over the frequency range of 57-65 GHz is less than 1 dB.
TL;DR: In this article, the gain of low temperature co-fired ceramic (LTCC) patch antenna arrays operating at 60 GHz is enhanced by introducing open air cavities around their radiating patches.
Abstract: The gain of low temperature co-fired ceramic (LTCC) patch antenna arrays operating at 60 GHz is enhanced by introducing open air cavities around their radiating patches. The open air cavities reduce the losses caused by severe surface waves and dielectric substrate at millimeter-wave (mmW) bands. The arrays are excited through either a microstrip-line or stripline feed network with a grounded coplanar-waveguide (GCPW) transition. The GCPW transition is designed so that the antenna can be measured with the patch array facing free space therefore reducing the effect of the probe station on the measurement. The proposed antenna arrays with the open air cavities achieves gain enhancement of 1-2 dB compared to the conventional antenna array without any open air cavity across the impedance bandwidth of about 7 GHz for |S11| ≤ - 10 dB at 60-GHz band.
TL;DR: In this paper, a simple and compact UWB printed monopole antenna with filtering characteristic is presented, which consists of a defected ground structure (DGS) and a radiating patch with arc-shaped step that is notched by removing two squares at the bottom.
Abstract: A simple and compact UWB printed monopole antenna with filtering characteristic is presented. The proposed antenna consists of a defected ground structure (DGS) and a radiating patch with arc-shaped step that is notched by removing two squares at the bottom. By using a modified shovel-shaped defected ground structure, band-notched characteristic that in volves both operating frequency band of Dedicated Short-Range Communication (DSRC) systems and WLAN is obtained. Omnidirectional H-plane radiation patterns and appropriate impedance characteristic are the main features of the proposed antenna that are achieved by designing the lower edges of the radiating patch in the form of arc-shaped step. The designed antenna has a small size of 15 × 18 mm2 and provides the impedance bandwidth of more than 128% between 3.1 and 14 GHz for VSWR <; 2, with notch frequency band at 5.13-6.1 GHz.
TL;DR: In this paper, a planar MIMO for UWB communications is presented, where two circular disc monopole antenna elements constitute the proposed UWB-MIMO antenna operating over the frequency band of 3.2{10.6GHz.
Abstract: A compact printed and planar Multiple-Input Multiple- Output (MIMO) for Ultra Wideband (UWB) communications is presented. Two circular disc monopole antenna elements constitute the proposed UWB-MIMO antenna operating over the frequency band of 3.2{10.6GHz. The isolation between the antenna ports has been enhanced to the value of more than 15dB throughout the frequency band of interest. This enhancement is achieved by taking the advantage of an inverted-Y shaped stub that is being inserted on the ground plane of UWB-MIMO antenna. The insertion of the stub has also facilitated reduction of the size of the antenna, i.e., overall dimensions of the antenna are 40 £ 68mm 2 . The proposed antenna is investigated both numerically and experimentally.
TL;DR: A set of external tuning circuits were designed to demonstrate the potential of the proposed configuration for applications where some level of reconfigurability is required and to improve the isolation between the wideband and narrowband ports several modified arrangements were presented and investigated.
Abstract: An integration concept for multi-standard antennas is described. This technique is based on utilizing a relatively large antenna that is printed on the top side of a substrate, acting as a ground for a smaller antenna. The smaller antenna is printed onto the bottom side of the substrate. To validate this concept, an integrated wide-narrowband demonstrator antenna is presented. This antenna is composed of a shorted microstrip patch integrated with a coplanar waveguide (CPW) fed ultrawideband (UWB) antenna. A prototype of the integrated antenna was fabricated and its performance was verified. This arrangement is a promising candidate for applications where some level of reconfigurability is required. For this reason, a set of external tuning circuits were designed to demonstrate the potential of the proposed configuration for such applications. In order to improve the isolation between the wideband and narrowband ports several modified arrangements were presented and investigated.
TL;DR: In this paper, a wide-slot antenna with microstrip-fed monopole for ultrawideband (UWB) application is presented, where the monopole is composed of an elliptic patch connected to a trapezoid one and the radiator patch is attached to a 50-Ω microstrip feed line by a smoothly tapered line.
Abstract: This is a presentation of a compact wide-slot antenna with microstrip-fed monopole for ultrawideband (UWB) application. The monopole is composed of an elliptic patch connected to a trapezoid one. The radiator patch is attached to a 50-Ω microstrip feed line by a smoothly tapered line to enhance the wideband matching. A hexagonal slot is etched from a finite ground plane placed on the other side of the substrate. The antenna has compact physical structure and is designed on standard FR4 substrate. Simulation and optimization with Ansoft HFSS and CST Microwave Studio software indicate 145% fractional impedance bandwidth varying from 2.9 to 18 GHz for VSWR less than 2. The antenna is successfully fabricated and characterized by measuring VSWR, radiation pattern, and gain. Comparison between simulated and experimental results exhibits a near agreement in the operating band. In addition, it yields an average gain of several decibels with low tolerance and reasonable stable radiation characteristics. The effects of vital parameters on antenna performance and some other details are analyzed and discussed as well.
TL;DR: In this paper, a new antenna with both frequency and polarization reconfigurability is presented, which consists of a square microstrip patch with a single probe feed located along the diagonal line, connected to a shorting post via a p-i-n diode for polarization switching and two varactor diodes for frequency tuning.
Abstract: A new antenna with both frequency and polarization reconfigurability is presented. The antenna consists of a square microstrip patch with a single probe feed located along the diagonal line. The center of each edge of the patch is connected to a shorting post via a p-i-n diode for polarization switching and two varactor diodes for frequency tuning. By switching between the different states of the p-i-n diodes, the proposed antenna can produce radiation patterns with horizontal, vertical, or 45° linear polarization. By varying the dc bias voltage, the operating frequency of each polarization of the antenna can be independently tuned. The frequency tuning range is from 1.35 to 2.25 GHz (|S11| <; -10 dB) for either horizontal or vertical polarization and from 1.35 to 1.9 GHz for the 45° linear polarization. Measured results on frequency tuning ranges and radiation patterns agree well with numerical simulations.