Showing papers on "Folded inverted conformal antenna published in 2001"

Novel compact circularly polarized square microstrip antenna

Abstract: A novel compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated. Experimental results show that the proposed compact CP design can have an antenna-size reduction of about 36% as compared to the conventional corner-truncated square microstrip antenna at a given operating frequency. Also, the required size of the truncated corners for CP operation is much greater than that for the conventional CP design using a simple square microstrip patch, providing a relaxed manufacturing tolerance for the proposed compact CP design. Details of the experimental results are presented and discussed.

A shared-aperture dual-band dual-polarized microstrip array

Abstract: This paper describes the design and testing of a prototype dual-band dual-polarized planar array operating at L- and X-bands. The primary objectives were to develop new antenna technology with dual-band and dual-polarization capability in a shared aperture, featuring low mass, high efficiency, and limited beam scanning. The design of a prototype planar microstrip array of 2/spl times/2 L-band elements interleaved with an array of 12/spl times/16 X-band elements that meets these requirements is discussed in detail and measured results are presented. The array is modular in form and can easily be scaled to larger aperture sizes.

Gap-coupled microstrip array antenna for wide-band operation

Abstract: The theoretical and experimental investigations carried out on a gap-coupled microstrip array antenna reveal that there is a significant improvement in VSWR and bandwidth characteristics of the gap-coupled microstrip array antenna as compared with a conventional microstrip array antenna. The input impedance and the resonant frequency of the gap-coupled patch are found to depend heavily on the gap length as well as on the dielectric constant of the substrate material.

A novel dual-band printed inverted-F antenna

Abstract: This paper proposes a novel dual-band printed inverted-F antenna, and a constructed prototype suitable for applications in the WLAN (2400–2484 MHz) and HIPERLAN (5150–5350 MHz) systems is presented. The antenna consists of two stacked inverted-F strips printed on a dielectric substrate, and sharing a common shorting pin which short circuits the two strips to the ground plane on the other side of the dielectric substrate. The proposed antenna can easily be fed by a 50 Ω microstrip line printed on the same substrate. Details of the proposed antenna and experimental results of the constructed prototype are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 353–355, 2001.

Broadband dual-polarized microstrip notch antenna

Abstract: A dual-polarized radiator for a phased array antenna includes two planar microstrip notch elements that interlock and are perpendicular to each other having their phase centers coincident to provide advantageous operational characteristics when the elements are used to form a wide bandwidth, wide scan angle phased array antenna.

Tuning techniques for planar inverted-F antenna

Abstract: User terminals of modern mobile communication systems require efficient, low profile antennas, capable of broadband and multi-band operation. In that respect, planar inverted-F antenna (PIFA) designs have emerged that explore the trade-off between the height above the ground-plane and the achievable effective bandwidth. Further possible bandwidth enhancements are studied, as is multi-band operation by switching and tuning the resonant frequency of the PIFA, while maintaining a low height above the ground plane.

Built-in dual frequency antenna

Abstract: An upright style built-in dual frequency antenna comprising an electric circuit board of a microstrip antenna, wherein, a microstrip of a small width in the form of continuous waves connected on the two ends thereof to two horizontal microstrips of larger widths together forming the microstrip antenna is printed on one side of the electric circuit board, the electric circuit board of microstrip antenna is installed upright in the top portion of communication equipment, an elastic metallic connecting member is connected with an antenna circuit of a main board of a communication device and with one of the horizontal microstrips of a larger width; a printing surface of the electric circuit board of the microstrip antenna faces to the top of the communication device without impediment of any metallic member. Thereby, it can get an ideal signal emitting and receiving performance with such a hidden structure.

Dual band patch antenna

Abstract: A dual band patch antenna (700) comprises a conventional patch conductor (106) having a resonant circuit (702, 704) connected between the patch conductor and a ground conductor (102). The resonant circuit (702, 704) modifies the behaviour of the antenna (700) in the vicinity of its resonant frequency, thereby providing a dual band antenna in which both bands can be used simultaneously. The total radiating bandwidth of the dual band antenna is significantly greater than that of an equivalent antenna having no resonant circuits. Additional resonant circuits can be employed to provide a multi-band antenna.

Dual feed internal antenna

Abstract: A dual feed internal antenna is disclosed which provides an internal antenna with multiple frequency response through the use of two or more internal antennas within one package. Each internal antenna has its own feed and ground connection. For example, a planar inverted F antenna provides response at cellular telephone frequencies and an inverted F antenna provides response at Industrial, Scientific, and Medical (ISM) band of frequencies.

Experimental study of large bandwidth three-offset microstripline-fed slot antenna

Abstract: The proposed novel three-offset shaped microstripline-fed slot antenna has a radiation pattern similar to the conventional microstrip slot antenna and the advantage of more bandwidth. The measured bandwidth is approximately 1.796 octave (VSWR/spl les/2.0), Experimental results for the impedance loci and the radiation patterns are also presented.

Wideband microstrip leaky-wave antenna and its feeding system

Abstract: A wideband microstrip leaky-wave antenna, comprising a plurality of sections of antenna. Each section of antenna includes a major part of microstrip antenna, each of which has different and continuous width parameters and is connected serially by the way in which the width parameters of major part of microstrip are decreasing. Each band of each antenna's section constructs a continuous antenna's band. In addition, To prevent characteristic of bandwidth from limiting, the antenna can include a wideband feeding system. The wideband feeding system comprises at least one conductor-backed coplaner strips connected to major part of wideband antenna, a balun connected to the conductor-backed coplaner strip, and an input microstrip connected to the balun. The input microstrip is utilized for energy input, then transmitting energy to the end of the section antenna through the conductor-backed coplaner strip and the balun.

Structural antenna for flight aggregates or aircraft

Abstract: A folded microstrip antenna for a flight aggregate or aircraft can be arranged around edges of thin structural parts, such as wings, tail units or control flaps, such that its surface is identical with the structure and folding takes place at the edge of the structure. The antenna is constructed such that its characteristic impedance is much higher at the folding edge than at ends of the structural antenna away from the edge. As a result, an approximately omnidirectional characteristic can be achieved.

Resonance behavior of single U-slot and dual U-slot antenna

Abstract: The broadband characteristic of a microstrip patch antenna with a U-shaped slot has been confirmed by many published results, in which two different but close resonant frequencies in a single patch are combined to give a wideband operation. On the other hand, if the excited resonant frequencies are far apart, a dual-frequency operation can be achieved with the U-slot antenna. In the present work, the resonance behavior of a single U-slot microstrip patch antenna is studied. Two approximate equations for the operating frequencies of a single U-slot microstrip patch antenna are derived by analyzing the surface current distribution on the microstrip patch. The two proposed equations for the operating frequencies of a single U slot antenna are accurate within about 5%. The design simulation results of a microstrip patch antenna with two asymmetric U-shaped slots for dual-frequency operation are also presented. The two operating frequencies of the proposed antenna are found to have the same polarization and similar broadside radiation characteristics. The frequency ratio of the two operating frequencies is found to be f/sub 2//f/sub 1/=1.57. The details of the antenna design and simulation results are presented and discussed.

Wideband microstrip patch antenna with planar PBG structure

Abstract: Microstrip antenna technology has found applications in a wide variety of military and commercial applications due to its many advantages (e.g. low profile, light weight, ease of fabrication, low cost). However, a narrow impedance bandwidth is a major drawback for this type of antenna. Thus, much of the research on microstrip antennas has been devoted to various techniques for increasing the impedance bandwidth. An electrically thick substrate with a low dielectric constant increases the bandwidth, but the impedance locus becomes increasingly inductive, making impedance matching difficult. In addition, surface waves are excited that lower the antenna efficiency. One technique used to suppress surface wave propagation in the antenna substrate to achieve better performance is photonic band gap (PBG). We describe a square patch with a wide impedance bandwidth. The multiple resonance technique has been used to obtain wider the bandwidth for this single feed antenna. The antenna also provides circular polarization within the bandwidth with a good axial ratio (AR). This patch has further been investigated by integrating it with a planar PBG structure; a significant improvement has been observed in both impedance and AR bandwidth. Antennas and the PBG structure are modeled with the finite-difference time-domain (FDTD) method.

A folded loop antenna system for handsets

Abstract: A unique folded loop antenna for handsets has been analyzed. The folded loop antenna is constituted by the concept of integration, by which the mode increase and small sizing are achieved. It has been shown that the folded loop antenna shaped like a half-wave folded dipole has similar structure as the balanced system and so almost no unbalanced currents flow on the ground plane as well. Thus with this structure, mitigation of the antenna performance degradation due to the body effect can be made possible. Another uniqueness of this antenna lies in the use of a two-wire transmission line for the antenna element. The antenna impedance can be adjusted flexibly by changing the parameters of the transmission line. By this means, matching can be made easy without using a balun.

A compact and broadband microstrip patch antenna

Abstract: A novel square microstrip patch antenna with a single-patch and single-layer structure is demonstrated. By incorporating an air-filled substrate with a thickness of around 0.08 /spl lambda//sub 1/ and having one patch edge shorted with three shorting-pins, an impedance bandwidth (return loss <-10dB) of 67.5% from 3.62 GHz to 7.32 GHz is obtained for this probe-fed compact and broadband antenna. The details of antenna design, analyses, and measurement results are presented and discussed.

A loaded inverted‐F antenna for mobile handsets

Abstract: This paper describes the design, measurement, and modeling of a linear inverted-F antenna with loading to increase the impedance bandwidth. In this case, two L-shaped wire structures are connected to the open end of the inverted-F element, yielding an impedance bandwidth of 10% in the 1800 MHz band. Measurements of return loss, impedance bandwidth, and gain are presented. The radiation pattern and polarization purity are discussed. The modeling of the antenna is based on a method of moments/GTD technique. A comparison with experimental results is presented. A comparison is also made with the popular planar inverted-F antenna. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 226–228, 2001.

Single-patch and single-layer square microstrip antenna with 67.5% bandwidth

Abstract: A square microstrip patch antenna with broadband operation is demonstrated. With an air-filled substrate of thickness around 0.1/spl lambda//sub 0/ and one patch edge shorted by three symmetrical shorting pins, the antenna achieves an impedance bandwidth (return loss /spl les/-10 dB) of 67.5%. The broadband feature of the antenna is mainly realised by exciting three resonant modes in a single patch and making them sufficiently close to one another. Details of the antenna design, equivalent circuit, and typical characteristics are presented and discussed both theoretically and experimentally.

A novel U-shaped planar microstrip antenna for dual-frequency mobile telephone communications

Abstract: We present a novel configuration of a U-shaped dual-frequency single feeding port planar inverted-F microstrip antenna for mobile communication applications in both the GSM and DCS 1800 systems operated at 0.9 and 1.8 GHz, respectively. Starting from an initial design derived from an empiric approximation and transmission line model for a standard rectangular microstrip antenna, we analyze, tune, and optimize the electric performance of the antenna and its dimensions by means of the generalized nonuniform finite-difference time-domain (NU-FDTD) Maxwell's solver.

Shorted fractal Sierpinski monopole antenna

Abstract: The novel configuration of a shorted fractal Sierpinski gasket antenna is proposed. The new configuration is similar to the inverted L antenna and the shorted loop monopole. Using only half the Sierpinski gasket structure, the symmetrical side is folded over to be parallel to the ground plane. While the 50/spl Omega/ feed remains at the apex, a shorting pin is placed at the far end of the gasket. A planar configuration of this design is also demonstrated.

Antenna systems including internal planar inverted-F antennas coupled with retractable antennas and wireless communicators incorporating same

Abstract: Antenna systems for use with wireless communicators, such as radiotelephones, are provided and include a first antenna configured to be internally mounted within a wireless communicator and a retractable, second antenna that couples with the first antenna when extended. The internal, first antenna is resonant within one or more frequency bands and the retractable, second antenna couples with the internal, first antenna so as to enhance one or more of the resonant frequency bands of the internal, first antenna.

Size reduction of microstrip antennas

Abstract: A scheme to reduce the size of a microstrip antenna is investigated both theoretically and experimentally. For a given operating frequency the patch length is significantly reduced when microstrip width discontinuities are introduced in the middle of the antenna patch.

Dual-band and wide-band PIFA with U- and meanderline-shaped slots

Abstract: This paper describes a novel dual-band planar inverted-F antenna (PIFA) for which the impedance bandwidth can be remarkably improved. The proposed PIFA uses a single feed only. Two top plate geometries, a U-shaped and a novel meanderline-shaped slot, are discussed. An example is given for frequency bands of 2.4 GHz and 5.2 GHz. Simulation based upon the method of moments is used to model the performance of the antennas. Comparisons with measured results on fabricated antenna structures are provided for simulations validation.

Excitation of low-profile equilateral-triangular dielectric resonator antenna using a conducting conformal strip

Abstract: A new configuration that employs a conducting conformal strip to excite the low-profile equilaterial-triangular dielectric resonator antenna (DRA) of very high permittivity is proposed. As compared with the previous aperture-coupling configuration, the new configuration has a wider impedance bandwidth (∼5.5%) and a higher front-to-back radiation ratio. The return loss, radiation patterns, and antenna gain are measured and discussed. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 317–319, 2001.

Tunable PIFA antenna

Abstract: A tunable PIFA antenna is disclosed for use with wireless communication devices. In three embodiments of the invention, a movable tuning member constructed of a high-dielectric constant material is selectively moved with respect to the feed and shorting pins of the antenna to vary the frequency response of the antenna. In the fourth embodiment, a slot is molded into the frame of the antenna. The size and position of the slot is varied by the molding tool to vary the frequency response of the antenna.

Compact circularly polarized pentagon-shaped microstrip antenna with bent slots

Abstract: A nearly equilateral-pentagon microstrip antenna with four bent slots to perform compact CP radiation is experimentally investigated. Results show that the modified equilateral-pentagon microstrip antenna can be visibly reduced in size to be about 36 %. as compared to the nearly equilateral-pentagon microstrip antenna. Also, good CP radiation is observed.

Housing-integrated planar inverted-F antenna for multiband mobile radio terminal has device for switching resonant frequency e.g. by grounding antenna area

Abstract: A switching device is provided for switching the resonant frequency between transmit and receive operation. The antenna volume is reduced using a similarly constructed arrangement without the switching device. The switching device may operate in at least two, preferably all frequency bands for which the antenna is designed. The switching device may alter the resonant frequency by about 5%, and act by grounding a selected terminal of an antenna surface.

Resonance Frequencies of Compact Microstrip Antenna

Abstract: A simple technique for calculating the resonance frequencies of a compact arrow-shaped microstrip antenna is presented and discussed. The accuracy of the method is validated by experimental results.