Small Patch Antenna Research Articles

Study of small wideband folded-patch-feed antennas

A small wideband patch antenna which exhibits an impedance bandwidth (Voltage Standing Wave Ratio (VSWR) ≤ 2) of more than 70% with an antenna size of 0.314λo×0.314λo×0.146λo (where λo is the guided wavelength of the centre operating frequency) is presented. Bandwidth broadening is achieved by an E-shaped patch fed by a folded-patch feed, whereas the size reduction is realised through the use of a shorting wall. As the antenna can be made from a single piece of copper plate, it is easier to fabricate than the wideband U-shaped-slot and L-shaped-slit folded-patch-feed antennas previously reported. Parametric studies of the proposed antenna are performed numerically to review its radiation mechanism. These include the purposes of having a shorting wall and two arms attaching on the upper patch forming the E-shaped pattern and the analysis of the input impedance of the antenna. Approximate equations for designing the proposed antenna are also presented. To verify the working principle, the proposed antennas are fabricated and tested for three different frequency bands. Stable radiation patterns are obtained across the band.

Development of an Accurate Positioning System Using Low-Cost L1 GPS Receivers

Abstract: The present article reports the development of an accurate positioning system based on GPS technology. This system employs an inexpensive L1 GPS receiver and a small patch antenna. As these devices are very inexpensive and small, they can be attached to an array of sensor nodes of a wireless network sensing system. In the present study, we first develop a program that can be used to estimate the relative positions of receivers and evaluate its performance. Next, a number of experiments were conducted to assess the performance of the inexpensive L1 GPS receiver with a patch antenna. Compared to the results obtained using a sophisticated antenna, the present measurement system, which uses a patch antenna, is less accurate. However, the present system achieves an accuracy of 1–2 cm. This system can be used as a localization system for the sensor nodes or, because of its accuracy, as a displacement monitoring system.

Wideband and small size star-shaped microstrip patch antenna

A new wideband and small size star-shaped patch antenna, fed by a small rectangular patch, is proposed. Simulation via a finite element program and measured results of return loss, and the E- and H-plane radiation patterns of the proposed antenna, are presented. The antenna is able to achieve in the range 5–9.3 GHz an impedance bandwidth of 63% for return loss of less than −10 dB.

A substrate for small patch antennas providing tunable miniaturization factors

Magnetic properties were imparted to a naturally nonmagnetic material by metallic inclusions. A patch antenna tested the performance of the magnetic metamaterial as a substrate and validated that a single substrate can achieve a range of miniaturization values. The effective medium metamaterial substrate employed electromagnetically small embedded circuits (ECs) to achieve permeability and permittivity greater than that of the host dielectric. Geometric control of the ECs allowed mu and epsi to be tailored to the application. The magnetic metamaterial exhibited enhanced mu and epsi with acceptable loss-factor levels. Models for predicting mu and epsi are presented, the benefits of employing metamaterial substrates are discussed, and the results in this antenna experiment are presented. The metamaterial exhibits performance characteristics not achievable from natural materials. Of particular significance is that with the permeability varying strongly and predictably with frequency, the miniaturization factor may be selected by tuning the operating frequency. Simulations indicate that such performance can be extended to several gigahertz with current technology. Relative permeability values in the mu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> =1-5 range are achievable for moderately low-loss applications. Representative antenna miniaturization factors on the order of 4-7 over a moderate (approximately 10%) transmission bandwidth and efficiencies in a moderate range (20%-35%) are demonstrated with the possibility of higher efficiencies indicated

Loading effect of dielectric resonator on small patch antennas

The characteristics of two dielectric resonator (DR)-loaded patch antennas with dielectric constants different from those of the supporting DR are investigated. The effect of the different dielectric constants of the supporting DR on the conventional patch antennas is studied. A sharp decrease in bandwidth is found if the dielectric constant of the DR is changed from ϵr = 3 to ϵr = 4. It can be concluded that a wider bandwidth can be achieved only if the appropriate dielectric constant of the supporting DR is chosen. It is also deduced that the design of DR-loaded patch antennas achieve more than 10% impedance bandwidth if the dielectric constant of the DR is smaller than 3. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 86–88, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21269

Dual-band circularly polarized microstrip antenna for satellite applications

This letter presents a dual-band circularly polarized patch antenna dedicated to satellite communications. The dual-band behavior is obtained by inserting a small X-band microstrip patch antenna into a large L-band one. Both patches are printed on the same substrate and fed by electromagnetic coupling through two perpendicular slots etched in their ground planes. These slots are fed by two different 90/spl deg/ microstrip branch-line couplers printed on a stacked lower substrate. A prototype of the antenna was realized with a 1.5-mm-thick upper layer substrate and a 0.758-mm-thick feed layer substrate, both of the same dielectric material with a relative permittivity of /spl epsiv//sub r/=2.22. Simulation and measurement results are presented, showing this compact dual-band antenna achieves the required Meteosat specifications in terms of frequency bandwidth, circular polarization bandwidth, and isolation between the two communication bands.

Stacked H-Shaped Microstrip Patch Antenna

A small H-shaped microstrip patch antenna (MPA) with enhanced bandwidth is presented. The H-shaped antenna is first studied by a transmission line model and then is fully analyzed with a MoM code. A stacked patch configuration is proposed to increase the narrow bandwidth, radiation efficiency and directivity. The stacked H-shaped MPA is studied using Chu's fundamental limit for electrically small antennas.

Study of a small wide-band patch antenna with double shorting walls

A small wide-band patch antenna with double shorting walls is presented. By employing two shorting walls and an additional aperture on the upper patch of a folded patch feed antenna, a 0.365/spl lambda//sub 0/ patch antenna with impedance bandwidth of more than 70% (VSWR/spl les/2) is achieved experimentally. Measured radiation patterns and gain across the frequency band are given.

Wideband small patch antenna

A small patch antenna fed by a coaxial probe with a wideband characteristic is presented. By employing dual shorting pins and cutting a slot in the patch, the size of the patch antenna is reduced while its impedance bandwidth is enhanced. The resonant frequency can be reduced by /spl sim/75% when compared with the resonance edge of a conventional patch antenna. The antenna has an impedance bandwidth of 21.5% (SWR<=2) and maximum gain of 2.2 dBi.

Computer-aided design of small patch antenna using (Al, Mg)TaO2 ceramics

The microwave dielectric properties of \(\left( {1 - x} \right)\left( {Al_{1/2} Ta_{1/2} } \right)O_2 - x\left( {Mg_{1/3} Ta_{2/3} } \right)O_2\) (AMT) \(\left( {0 \leqslant x \leqslant 1.0} \right)\) ceramics and the design of small coplanar waveguide fed antenna (CPWFA) have been investigated. (\(\left( {Al_{1/2} Ta_{1/2} } \right)O_2\) and (\(\left( {Mg_{1/3} Ta_{2/3} } \right)O_2\) have orthorhombic and tetragonal structure, respectively. As (\(\left( {Mg_{1/3} Ta_{2/3} } \right)O_2\) concentration increased, AMT ceramics transformed into the tetragonal structure. Specimens having tetragonal single phase could be obtained above x=0.6. As (\(\left( {Mg_{1/3} Ta_{2/3} } \right)O_2\) concentration increased, the grain size, dielectric constant \(\varepsilon _r\) and quality factor (Q) significantly increased and the temperature coefficient of resonant frequency \(\tau _f\) changed from negative to positive. The \(\tau _f\) of \(0 ppm ^\circ C^{ - 1}\) was realized at x=0.65 and the Q · fO value and \(\varepsilon _f\) for this composition were 112 470 GHz and 26.1, respectively. Newly developed \(0.35\left( {Al_{1/2} Ta_{1/2} } \right)O_2 - 0.65\left( {Mg_{1/3} Ta_{2/3} } \right)O_2\)dielectric materials were used for 1.5 GHz band CPWFA design and fabrication. The size of the CPWFA can be reduced by using high dielectric constant AMT ceramics, insetting slits into the patch, and fabricating CPW feed line in the ground plane. The slits play a role in not only lowering a center frequency but also fine tuning for the proposed antenna together with the open stub of CPW feed line. The CPWFA with slits has a lower center frequency than the conventional CPWFA, which suggests that the antenna size can be reduced by as much as 16.3%. The structure simulations of the CPWFAs have been performed to obtain impedance matching and to investigate the effects of slits. Experimental results of the fabricated device were in good agreement with the simulation.

Small and high‐directivity bow‐tie patch antenna based on the Sierpinski fractal

AbstractThe unique geometrical properties of fractals have been proven to be useful to design advanced antennas. Enhanced performance in terms of size, gain, or multifrequency behavior is observed in fractal‐shaped antennas. Here, a small and high‐directivity antenna based on the Sierpinski fractal is presented. © 2001 John Wiley &amp; Sons, Inc. Microwave Opt Technol Lett 31: 239–241, 2001.

Small printed‐wing antenna suitable for wireless handset terminals

AbstractA novel, small winged microstrip patch antenna incorporating a single shorting post is introduced. The proposed antenna is significantly smaller than a conventional shorted patch antenna, and is therefore very suited to wireless communication handsets where limited antenna size is a premium. Importantly, the antenna is easy to develop. An integrated version of the proposed antenna on a standard communication handset chassisep is also presented, and its performance is compliant with most cordless systems requirements. © 2001 John Wiley &amp; Sons, Inc. Microwave Opt Technol Lett 30: 226–229, 2001.

A double‐folded, capacitive‐fed, cavity‐backed microstrip antenna

AbstractA novel, folded, capacitive‐fed microstrip antenna with a length of λ/3 and placed over a cavity backing is proposed. Compared to the small rectangular patch antenna of Luk, our proposed antenna has a large impedance bandwidth of 20.1%. The cross‐polarization level is ∼−17 dB. © 2001 John Wiley &amp; Sons, Inc. Microwave Opt Technol Lett 30: 240–241, 2001.

Small wideband triangular patch antenna with an L‐probe feeding

AbstractExperimental results for an L‐probe‐fed shorted triangular patch antenna are presented. Using a foam layer of thickness ∼0.13λ0 as a supported substrate, an impedance bandwidth of 61% (SWR≤2) and a gain of over 4.0 dBi in the bandwidth have been obtained. The far‐field patterns are stable across the passband. © 2001 John Wiley &amp; Sons, Inc. Microwave Opt Technol Lett 30: 218–220, 2001.

Small broadband semicircular patch antenna with an L‐probe feeding

Small broadband semicircular patch antenna with an L‐probe feeding

Small broadband semicircular patch antenna with an L‐probe feeding

AbstractExperimental results for an L‐probe‐fed shorted semicircular patch antenna are presented. Using a foam layer thickness ∼0.12λ0 as a supported substrate, an impedance bandwidth of 57% (SWR≤2) and a gain of over 4.0 dBi in the majority of the wide bandwidth have been obtained. The far‐field patterns are stable across the passband. © 2001 John Wiley &amp; Sons, Inc. Microwave Opt Technol Lett 29: 289–290, 2001.

FDTD analysis of a compact microstrip antenna with a C-shaped slot

A novel small microstrip patch antenna with a C-shaped slot is presented in this paper. The size of the antenna is only 33% of a conventional microstrip patch antenna, and is much easier for fabrication than shorted patch antennas. The antenna is theoretically investigated using the finite-difference time-domain (FDTD) method, and its return loss and radiation properties are presented. For purposes of comparison, method-of-moment (MoM) results are also presented, and good agreement is achieved. Such an antenna may be useful for applications where reduced antenna size and simplicity are major concerns. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 170–172, 2001.

Small dual patch antenna

A novel two-layer rectangular patch antenna has been designed and tested. Compared with a basic single layer patch antenna with the same projection area, the resonant frequency is reduced by 39%. The bandwidth is 5%; the cross-polarisation level is less than –15 dB.

Small rectangular patch antenna

A novel folded rectangular patch antenna is designed and measured. Compared with a conventional patch antenna with the same surface area, the resonant frequency is reduced by 37%. The cross-polarisation level is ~–20 dB.

A small microstrip patch antenna with a convenient tuning option

The paper addresses two aspects of resonant microstrip patch antennas, namely, miniaturization and resonant frequency tuning. First, a patch geometry which allows a controllable size reduction over a limited range is presented. The basic shape is circular with slits cut into it. Modification of the slit geometry leads to both linear as well as circular polarized (CP) operation. Second, the use of another patch of a specific shape as a superstrate layer in a stacked configuration allows tuning over a relatively large frequency range as compared to the patch bandwidth. Tuning is accomplished by a simple rotation of the superstrate layer. The use of another superstrate layer allows tunable CP operation. Details on the antenna characteristics have been worked out for two examples, and computations have been compared with measurements where possible. Some design guidelines have also been included.