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This paper presents a quad-band frequency agile antenna, with independent and concurrent frequency tunability in each band, for a tunable, concurrent, quad-band single chain radio receiver for 5G New Radio (NR). More specifically, the antenna comprises of four planar slots etched in a ground plane and fed through a single microstrip feedline, without any impedance matching network. The structure is optimized to maximize isolation between the individual slots and their respective resonant frequencies. Furthermore, a novel high order harmonic suppression method is demonstrated, which controls the current distribution via creating a fictitious short circuit in the slot antenna–enabling the antenna to achieve a much wider tuning range. Numerical simulations are verified using experimental implementation and measurements, with good agreement observed. The four slots resonate around the 830 MHz, 1.8 GHz, 2.4 GHz and 3.4 GHz frequency bands, which are independently tuned (using a varactor diode in each slot) to achieve tuning ranges of approximately 64%, 66%, 27% and 33%, respectively. More importantly, the contiguous four bands covers a total frequency tuning from 0.6 to 3.6 GHz i.e. a tuning range of approximately 143%. Finally, far-field measurements are performed and the antenna is evaluated in over-the-air testbed (quad-band radio receiver), which measures the Error Vector Magnitude performance for the individual channels. Good performance is observed, confirming acceptable isolation performance between the four bands. The data reported in this paper is available, from ORDA-The University of Sheffield Research Data Catalogue and Repository, at https://doi.org/10.15131/shef.data.11219000.v1 .

Novel arrangements of active frequency selective surfaces (AFSSs) with integrated voltage control wiring are proposed for bistate (transparency/reflectance) operation at specified frequencies. The AFSSs are comprised of passive arrays of intertwined patterns of slots in a conductor screen and an active dipole array with p-i-n diodes placed on either the same or opposite sides of a thin dielectric substrate. Simulation and measurement results show that such AFSSs exhibit good isolation (~15 dB) between the translucency and reflection states at normal incidence that slightly decreases at oblique incidence. The proposed AFSSs maintain the high angular and polarization stability over broad fractional bandwidths inherent to the constituent periodic arrays of intertwined conductor patterns with substantially subwavelength unit cells. The merits of these AFSS arrangements also include resilience to parasitic effects of real switches, whose insertion loss in the ON state only enhances the AFSS ON/OFF isolation. Such AFSSs are essential elements for reconfiguring and controlling the electromagnetic architecture of buildings.

The design methodology is described for a miniaturized frequency selective surface (FSS) using lumped reactive components. Capacitive and inductive elements are utilized in metallic patches to create current loops similar to that observed in bandpass aperture type FSS. It is shown that the resonant frequency of the FSS is controlled mainly by the values of the lumped components and to a lesser extent by the distance between the components. It is insensitive to the periodicity. Issues such as the effects of component loss and oblique incidence are reported using full field predictions. Measurements are shown for an FSS with unit cell periodicity of ?/36.

A beamspace adaptive planar array for broadband beamforming is proposed based on the frequency invariant beamforming technique. A detailed analysis is provided for both the linear arrays and the planar arrays, where two conditions are imposed: the beams should exhibit a good frequency invariant property and be linearly independent. These two conditions are not independent and there is a tradeoff between them. To improve the interference cancellation capability of the array, we may need to sacrifice the frequency invariant property to some degree for more linearly independent beams. A sufficient condition for the linear independence of the beams is derived with a DFT matrix based design proposed. Simulation results verified our analysis and the proposed method.

A finite element model, using commercially available software, is presented to simulate the piezoelectrically induced stresses and strains in an optical fibre to be used as antenna. These stresses and strains are generated by a layer of piezoelectric polymer deposited on the cladding of a short fibre sample. The theoretical basis for the work is briefly explained and the modelling process is emphasised. Two types of fibre are investigated – circular fibre and D-fibre, and the results compared, analysed and discussed. It is shown that in the D-fibre, the stress and displacement increased by 1.46 and 115 times, respectively, in comparison with the circular fibre.

Conventional microstrip patch antennas are printed with continuous solid copper shapes and ground planes. The general properties of meshed patches are presented in this paper where both the patch itself and the ground plane are meshed. The gain, cross-polarization, bandwidth and radiation patterns are discussed for different combinations of patch and ground plane. The radiation patterns are not significantly affected by meshing the patch alone, but meshing the ground plane increases the back radiation. The gain can suffer by up to 3 dB or more when compared to a standard patch. Cross-polarization is improved providing that the correct mesh line geometry is chosen for the excitation mode. Meshing lowered the resonant frequency in some cases by up to 30% and also improves the bandwidth by a factor of up to 2.5 in some modes. Overall, the meshed patch offers a complex tradeoff between parameters but gives opportunities for improving the bandwidth and reducing the cross polarization and the antenna dimensions at the expense of the gain.

This Letter presents methods for improving the gain and efficiency of a microstrip patch antenna operating at 2.45 GHz implanted in the fat layer of the human body. Simulations using CST Microwave Studio are verified by measurements carried out in an anechoic chamber using a cut of fresh pork meat which has close electromagnetic characteristics to the human body. Using a glass lens and a parasitic ring placed on the skin the implanted antenna gain can be enhanced by almost 8.5 dB.

A new type of active frequency selective surface (AFSS) is proposed to realise a voltage controlled bi-state (transparent and reflecting) response at the specified frequencies. The bi-state switching is achieved by combining a passive array of interleaved spiral slots in conducting screens and active dipole arrays with integrated pin diodes at the opposite sides of a thin dielectric substrate. Simulation results show that such active surfaces have high isolation between the transparency and reflection states, while retaining the merits of substantially sub-wavelength response of the unit cell and large fractional bandwidths (FBWs) inherent to the original passive interwoven spiral arrays. Potential applications include reconfigurable and controllable electromagnetic architecture of buildings.

In this paper, the planar phased array antenna scan blindness characteristic has been analyzed and a novel technique of eliminating the scan blindness for the phased array antenna has been introduced. The scan blindness of the center element has been used to present the entire phased array characteristic. The array scan blindness characteristics have been simulated and analyzed using CST Microwave Studio (CST MWS). The 5×3 planar phased array antenna radiation patterns against the pattern elevation angle direction has been simulated and compiled. The array’s scan blindness has been determined at the angle of approximately 47⁰. The miniaturized capacitive loaded Electromagnetic Band Gap (EBG) has been developed and introduced between the array elements to eliminate the problem. Based on the simulated results, it is shown that the use of a miniaturized EBG is effective in reducing the surface wave effects and eliminates the scan blindness in the array radiation pattern. This novel finding is very useful to improve the antenna directive efficiency for the directional radar and satellite application.

Reconfigurable bi-state interwoven spiral FSSs are explored in this work. Their switching capability is realized by pin diodes that enable the change of the electromagnetic response between transparent and reflecting modes at the specified frequencies in both singly and dual polarised unit cell configurations. The proposed topologies are single layer FSS with their elements acting also as dc current carrying conductors supplying the bias signal for switching pin diodes between the on and off states, thus avoiding the need of external bias lines that can cause parasitic resonances and affect the response at oblique incidence. The presented simulation results show that such active FSSs have potentially good isolation between the transmission and reflection states, while retaining the substantially subwavelength response of the unit cell with large fractional bandwidths (FBWs) inherent to the original passive FSSs.

Reconfigurable bistate metasurfaces composed of interwoven spiral arrays with embeddedpindiodes are proposed for single and dual polarisation operation. The switching capability is enabled bypindiodes that change the array response between transmission and reflection modes at the specified frequencies. The spiral conductors forming the metasurface also supply the dc bias for controllingpindiodes, thus avoiding the need of additional bias circuitry that can cause parasitic interference and affect the metasurface response. The simulation results show that proposed active metasurfaces exhibit good isolation between transmission and reflection states, while retaining excellent angular and polarisation stability with the large fractional bandwidth (FBW) inherent to the original passive arrays.

This paper presents a novel switchable electromagnetic bandgap surface wave antenna that can support both a surface wave and normal mode radiation for communications at 2.45 GHz. In the surface wave mode, the antenna has a monopole-like radiation pattern with a measured gain of 4.4 dBi at ±49° and a null on boresight. In the normal mode, the antenna operates like a back-fed microstrip patch antenna.

This paper presents the performance of a textile patch antenna array under different bending conditions. Input impedance and radiation patterns are investigated based on numerical and experimental methods at 2.45 GHz. A 70 MHz resonant frequency shift is noticed when the array is bent around the X-axis with a 40mm radius. The array radiation characteristics are significantly changed when the array is bent at a small radius.

A conformai patch antenna operating in the TM01 mode is integrated over an electromagnetic bandgap surface (EBG) to provide a beam scanning antenna. The circular EBG elements are arranged in a sector pattern and the vias on each sector of the EBG are switched in and out to steer the beam into that sector. The reflection coefficients for the antenna when the vias are switched remain stable and experimental results validate the simulations. Overall a flexible beam scanned antenna is demonstrated.

A low profile antenna consisting of a wideband monopole over an artificial magnetic conductor (AMC) is presented in this paper. The AMC is a dual band structure, manufactured on 3.2mm thick FR-4 substrate with the reflection phase in the 2.0 GHz and 5.8 GHz ranges. A wideband printed circular disc monopole antenna uses this dual band AMC as a ground plane resulting in a low profile multiband antenna system with a height of 7.8mm. The frequency bands covered are at GPS (1.57542 GHz), DCS (1.710–1.880 GHz), PCS (1.850–1.990 GHz), UMTS (1.925–2.175 GHz), WLAN (2.4–2.485 GHz), WiFi (5.15–5.825 GHz) and V2X (5.76–5.84 GHz). It is demonstrated that the boresight gain increases when the AMC is used as a ground plane for the antenna in conjunction with a large metal plate.

Electromagnetic band gap surfaces (EBGs) are useful for in-phase reflection of electromagnetic waves acting as high impedance surfaces/artificial magnetic conductors (HIS/AMC) and the suppression of surface waves. The in-phase reflection characteristic allows antennas to be placed very close to the HIS which in turn can be placed on a metal ground plane resulting in compact conformal antennas ideal for positioning on metallic areas of a vehicle. The surface wave suppression feature improves the antenna gain and hence efficiency in the boresight direction [1]. A double square patch AMC is a dual band structure that has been used for several antenna applications [2, 3]. In this paper a novel dual band EBG based on the conventional double square patch EBG but with more band flexibility is presented combined with a small antenna aimed at the automotive market where antennas may be placed on the metal bodywork. Multi-frequency band flexibility for the UMTS 1.9 GHz band, WLAN 2.45 GHz band, WiFi at 5.15 GHz and 5.825 GHz and V2X 5.8 GHz band is achieved. The unit cell size measures 0.15λx0.15λ at the lowest operating frequency for the reflection phase bandgap.

The performance of a dual-band textile antenna under two-dimensional crumpling conditions is described. Both input impedance and radiation patterns are investigated based on numerical and experimental methods at 2.45 and 5.8 GHz. The return loss for the coplanar antenna is affected by the most severe crumpling at the higher frequency band, while the radiation patterns remain acceptable at both bands.

Numerical methods have been used to investigate the possible impact of various dielectric components of vehicles on internal electromagnetic field distributions for frequencies up to 2 GHz. The electrical parameters used in the models were derived from measurements on samples obtained from vehicle components. It is found that the dielectrics investigated have a relatively small impact on the internal field populations due to sources located inside the passenger compartment. Under plane wave illumination from the front, however, the dielectric parts dampen the low frequency resonances, while the glass reduces the internal fields for horizontal polarization. Simulations of lossy materials in a vehicle-like cavity indicate that it may be possible to reduce field levels using readily available materials.

We present a low cost fabrication method for THz filters utilising a metallic photonic-band gap structure on a plastic substrate. Measurements of the filters are made with a terahertz pulse spectrometer (TPS) and a THz monochromator in the 0.2-3 THz range and exhibit absorption band centered at frequencies of 0.72, 0.97 and 1.24 THz, with 3 dB bandwidths of less than 200 GHz. We further present some initial applications of the filters in TPS frequency calibration and explain how such filters can be used as an anti-counterfeiting product.

A dual frequency band triangular patch antenna is presented fabricated on clothing materials. The antenna operates over the wireless network bands at 2.45 Hz and 5 GHz. To reduce back radiation the antenna was placed over an electromagnetic band gap surface. Back radiation was reduced by 10 to 15 dB while maintaining the impedance match over the frequency bands.

The performance of a novel antenna designed to work on a ground plane with a wide frequency bandwidth is presented. The antenna uses two low profile elements that are fed via a single microstrip line. The overall height of the antenna was 7 mm and the base was 86 mm times 54 mm. A bandwidth of 2:1 is attained which is good for an element on a ground plane but not sufficient for UWB applications. The resulting radiation patterns are satisfactory across the band from 5 GHz to 10 GHz.

A compact and low profile internal antenna capable of operating in multiple bands is proposed. It consists of a long monopole ring, which is top-loaded by a helical element in order to produce two main resonances of wide bandwidth. Its compact size of length 10 mm, width 28 mm and height of 6 mm and small volume of 1.68 cm/sup 3/, makes it possible to be used internally, inside the mobile phone. With the help of a small matching circuit a VSWR < 3 is achieved covering the bands of GSM900 (880-960 MHz), DCS (1710-1880 MHz) and PCS (1850-1990 MHz). The efficiency is above 50% in all bands. The specific absorption rate (SAR) is also measured, presented and discussed in this paper.

This Letter discusses an experimental study and Hankel-domain analysis of annular ring patch antennas attached to a laminated glass vehicle windscreen. The fundamental TM(11) and higher-order TM(21), modes are studied, the latter being of interest for mobile satellite communications. Attaching the antenna to the screen brings about a doubling in the bandwidth, and adding a resistive ring on top of the screen further improves the bandwidth.

A novel multiband PIFA antenna is presented showing simulated modal current distributions and measured input impedance. All major mobile communications bands have been included and measurements show the radiation patterns to have good H-plane omnidirectionality at all bands.

Convolution and interleaving of periodic electromagnetic band gap (EBG) elements is investigated to reduce the band-gap frequency for fixed periodicity. A 42% reduction in band gap frequency is obtained when compared to a simple square patch element. Furthermore, interleaving adjacent convoluted elements reduces the band gap frequency by 55% when compared to the solid patch.

Interaction between an antenna and an enclosing FSS is investigated using the Pocklington equation approach from an earlier study of arbitrarily curved free-standing arrays of dipoles. Part of such a collection of elements can be regarded as a receiving antenna, and the rest can be distributed around it to form a dichroic enclosure. It is then possible to analyse this structure with and without mutual coupling between the two sets of dipoles, to give an indication of antenna-radome coupling in a simple case. >

Outlines a study incorporating convoluted elements to high impedance ground planes (HIPs) which are formed by electromagnetic band gap (EBG) structures. The aim of the work is to achieve a reduction in structure resonant frequency for a given EBG lattice geometry without requiring the extra complexity of additional capacitive layers.

The performance of circular microstrip patch antennas is presented where the conducting patch and ground plane are constructed from a grid. Improed cross polarization, mode suppression, and band- width are possible, but are accompanied by lower gain and reduced front-to-back ratios. A computer simulation reeals the current structure. The density and shape of the grid pattern are important parameters. Such antennas are can be manufactured within glass laminates. Q 1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 311)313, 1999. wx Microstrip antennas 1 consist of a printed conducting shape situated above a conducting ground plane. These conductors . are usually continuous solid . Rectangular printed antennas . where the patches are made from a conducting grid mesh wx have been reported previously 2 . Improved bandwidth, but lower gain were the main observations. There will be applica- tions, such as GPS and tolling, where it is desirable to print patch antennas within the glass laminate of a windscreenrrear screen. In the manufacturing process, it is not possible to use a solid silver patch or ground plane as this distorts the heating profile during lamination, causing structural distor- tions; hence, a gridded conducting structure must be used. This letter discusses the performance of a circular disk mi- crostrip patch antennas where the solid conducting printed patch and the ground plane are replaced by conducting grids of appropriate geometry for the mode of patch excitation. Performance is compared with an equivalent conventional patch in all cases. For this study, the patches were initially printed on RT Duroid substrate, 0.78 mm thick, with a relative permittivity of 2.33 so that an assessment of the effects of meshing the antenna could be made. In later work, the antennas were screen printed on glass. The performance of conventional patches with glass subtrates and superstrates wx

There is much interest in the use of ferrite substrates for microstrip patch antennas. The high dielectric constant of the ferrite brings about a reduction in the antenna dimensions. When biased with a magnetic field the antennas exhibit a number of novel properties. These include frequency tuning over a 15-40% range, the generation of two opposite hands of circular polarisation and beam steering possibilities. This paper discusses two aspects of circular microstrip antennas on ferrite substrates. The first is spectral domain modelling of the frequency tuning characteristics for a circular patch on a ferrite. Details of the model together with a comparison with experimental results are given. Phased arrays often use ferrite phase shifters to change the phase of individual elements and produce electronic beamsteering. We demonstrate a simple but effective means of controlling the beam angle from 2 and 4 element arrays where the patch elements are fed by a microstrip line on a ferrite substrate. Biasing the ferrite causes a shift in the phase length of the line hence varying the beam angle.

This paper presents results from a project studying horn antennas in which a change in beamwidth is produced by a corresponding change in an electronically variable input parameter. The beamwidth of a horn can be altered by changing either the effective transmitting aperture, and/or by modifying the amplitude/phase distribution over it. Initial experimental prototypes successfully demonstrated the feasibility of achieving as much as a 1:3 change in beamwidth with H-plane sectoral horns. The technique has now been successfully extended to pyramidal horns to produce variable patterns in both principal planes.

An annular slot on triplate feed is discussed which is suitable for use with vehicular mobile satellite systems. The slot is excited in a higher order mode and circularly polarised to give a conical radiation pattern. The slot can operate on a high dielectric base and a superstrate improves the gain.

Two dimensional periodic arrays of patch elements can be used as frequency selective surfaces (FSS) owing to the frequency filtering properties of these structures. Arrays of square loops are of interest as frequency selective surfaces for dichroic reflector antennas. This paper describes a new way for modelling and analysis of such FSS using the 3D transmission line matrix method and compares the transmission characteristics predicted by the TLM method with those obtained experimentally.

In order to study the effects of a dielectric embedded FSS on an enclosed antenna pattern, the authors adopt the ray tracing technique to compute the near field pattern of the antenna-FSS configuration exterior to the structure, from which the transmission coefficient and the far field patterns can be calculated. They use parabolic and paraboloidal shapes formed from a dielectric slab with an embedded slot ring FSS which, when it is planar, provides a flat passband transmission window. Rings have been chosen with a view to minimise polarization dependence of the element although the method is applicable to arbitrary FSS arrays and surfaces of arbitrary shape. The approach adopted is based on tracing multiple ray paths through the curved dielectric slab with the FSS treated as an infinitesimally thin interface with known reflection and transmission coefficients. In this manner, a structure composed of an FSS embedded in a dielectric can be treated as a series of interfaces where the incident ray is partially specularly reflected and partially transmitted according to the reflection and transmission dyadics at the point of incidence, until it emerges on the other side of the radome or decays to a level below a prescribed threshold. With a sufficiently dense bundle of input rays from the source, the radiation pattern transmitted through the radome can be computed using two dimensional interpolation on the transmitted rays.

An artificial magnetic conductor (AMC)-based multiband low-profile antenna for vehicle applications is designed, simulated and measured in this study. The AMC is a simple dual band structure, constructed on a 3.2 mm-thick FR-4 (e r =4.4) board, with the reflection phase and surface wave bandgaps in the 2.0 and 5.8 GHz ranges. A wideband printed circular disc monopole antenna uses this dual-band AMC as a ground plane resulting in a low-profile, multiband and platform-tolerant antenna system. The operating frequency bands covered are GPS (1.57542 GHz), DCS (1.710-1.880 GHz), PCS (1.850-1.990 GHz), UMTS (1.925-2.175 GHz), WLAN (2.4-2.485 GHz), WiFi (5.15-5.825 GHz) and V2X (5.76-5.84 GHz) using a -10 dB reflection coefficient criterion. It is demonstrated that the antenna gain increases significantly when the AMC is used over a large metal ground plane for the antenna.

A multimodal network formulation has been applied to existing equivalent circuits for frequency selective surfaces. An arbitrary number of modes can be included, with different dielectric media on each side of the surface. Predicted transmission responses more closely match the measured results with only a modest increase in computing power. The inclusion of the supporting substrate improves the model considerably. >

A compact dual-band antenna structure for automotive and aerospace applications is discussed. A bow tie dual-band electromagnetic band gap (EBG) element geometry is presented that has a reduced cell dimension compared to the wavelength yet has sufficient bandwidth for mobile communication applications. The EBG was combined with a printed planar monopole to produce a structure 8 mm thick. The return loss and radiation patterns gave satisfactory performance at two frequency bands with bandwidths of 11% at 1700 MHz and 7% at 2600 MHz. There was suppression of the back radiation at both bands of 5 dB or better even for the small 3 times 3 element EBG used and the antenna was platform tolerant.

A microstrip patch antenna operating in the 5 GHz range and tuned by liquid crystal (LC) is described. The simulated tuning range is 8 while the measurements showed a range of 4. Losses in the commercially available LC material at these frequencies give rise to antenna efficiencies ranging from 35 40 at best and falling to around 20 when the LC is in the unbiased state.

A triangular patch antenna with a parasitic element over a modified small ground plane is presented. The antenna operates at two frequency bands with bandwidths exceeding 20% at the 2.45 and 5 GHz network bands. The ground is modified by cutting a large rectangular slot in it that allows tuning of the frequency bands and adjustment of the band spacing ratio.

A vehicle diversity antenna system comprising a single-fed element together with a loaded parasitic element is described. Different termination loads on the parasitic element give rise to variations in the radiation patterns that are comparable with a four-element diversity system. There was good agreement between measured parameters and simulations.

An H-plane sectoral horn contains ferrite powder dispersed in a solid low-loss dielectric medium. The permeability of the medium is varied by an externally applied magnetic field to alter the phase distribution across the horn aperture to produce a variable beamwidth horn.

An experimental H-plane sectoral horn with interior active FSS wall in the E-plane is described. The FSS is switchable between transmitting and reflecting states, which enables the horn beamwidth to be varied.

Electromagnetic bandgap structures of simple squares are compared to convoluted and interleaved elements to reduce bandgap frequency for fixed periodicity. A reduction of 42% in bandgap frequency is obtained for one (Hilbert) convolution. This frequency reduction increases to 55% when adjacent elements in the structure are interleaved.

Properties of annular ring microstrip antennas printed on magnetically biased ferrite substrates are reported. Experimental results for the fundamental TM11 mode and a higher-order TM21 mode are described. Circular polarisation is generated using a single electromagnetically coupled feed for both modes. The resonance frequency can be tuned over a 15% range using a magnetic bias normal to the patch and ferrite.

The passband of a convoluted slot array is switched in frequency by exchanging liquid substrates. In the example illustrated, liquid with epsilon /sub r/ approximately= 2.2 gives a 3 GHz frequency shift and a 16 dB change in the transmission coefficient at 17 GHz.

A finite-element approach has been used to study the field distribution inside a simple building construction illuminated by a plane wave. To solve electromagnetic scattering problems for such electrically large dielectric objects, which can have losses and frequency selective surfaces in their construction, a hybrid FE method has been chosen. A numerical example demonstrates the contribution of an array of metal rods, such as are used for reinforcement in building work, to the transmission/reflection properties of the dielectric walls of a simple room, and the consequent effect on the fields inside. Computed field distributions are presented at frequencies where the equivalent wall grating transmittivities are high and low, but typical of values obtained with single-layer FSS.

A theoretical and experimental study of the phase characteristics of thick conducting gratings is presented. The frequency and angular behaviour of the reflection coefficient phase is investigated. Depending on the cross-section of the conductors, the grating periodicity can be chosen such that, over a wide frequency range, the phase of the reflection and transmission coefficients remains constant. Angular dependence of the reflection and transmission coefficients for these gratings also disappears within this frequency range. The phenomenon occurs only for the case with the electric vector parallel to the grating conductors.

The design and performance of circular microstrip patch antennas on biased ferrites are described. Fundamental and higher-order modes are discussed and measurements presented for two different ferrites. The high permittivity of the substrate reduces the dimensions of the patches. The cavity model is extended to include multilayer ferrite-dielectric substrates with electromagnetic feedline coupling to the patch. This provides an accurate and fast CAD tool for predicting the resonant frequency over a wide bias range. Applying a DC magnetic bias field normal to the ferrite allows tuning of the resonant frequency by about 15%. Two hands of circular polarisation are generated when the magnetic bias is applied. The resulting radiation performance of the patches, in terms of the gain and quality of circular polarisation, is presented. It is shown that the gain is not dependent on the applied bias field and that good axial ratios are measured over a wide range of bias fields, both above and below saturation magnetisation.

The performance of circular patch antennas attached to a laminated automotive windscreen is described. Experimental work and results computed from a spectral domain analysis investigate the input impedance, radiation patterns, and the effect of surface wave propagation within the glass. The overall efficiencies of several combinations of substrates and superstrates are presented. Variations in the dimensions of the laminate are discussed as they have a significant effect on patch performance.

Properties of a circular patch antenna with radiation characteristics similar to those of a resonant monopole are presented. The TM/sub 01/ mode excited patch on a small ground plane radiates a null on boresight and is easy to match to a 50 /spl Omega/ line. Applications include mobile vehicle applications and wireless LANs.