Stripline Feed Research Articles

Dual-polarisation and dual-pattern planar antenna for diversity in body-centric communications

A novel dual-polarisation/dual-pattern stripline-fed annular-ring slot antenna for body-centric communication systems working in the IEEE 802.11a frequency band at 5.725–5.825 GHz is presented. A stripline feeding technique has been implemented in order to reduce the back radiation level and make the antenna suitable for wearable communication systems. The planar antenna has been designed to provide capabilities for implementation of a polarisation/pattern diversity scheme in body-centric communications. Two prototypes have been fabricated and characterised. The design criteria are described and measurements of return loss, isolation between ports, principal plane radiation patterns and radiation efficiency are shown. A measurement campaign has also been carried out to evaluate the diversity scheme performance.

A Novel Approach for Realizing 2.4/5.2 GHz Dual-Band BPFs using Twin-Spiral Etched Ground Structure

This paper proposes a simple approach for realizing a dual-band response bandpass filter (BPF) comprising two strip feed lines on the upper layer and a twin-spiral etched ground structure (EGS) on the lower layer. It is shown that by moving the two strip feed lines from the center of the EGS toward the upper-left and lower-right corners of the EGS unit, respectively, a 5.2-GHz passband can be excited in addition to the original 2.4-GHz passband. Moreover, by carefully controlling a dimension of the EGS, the second passband can be tuned in such a way as to realize a 2.4/5.7 GHz BPF. The experimental results show that the dual-band 2.4/5.2 GHz BPF has a good passband selectivity and an excellent out-of-band noise suppression capability. Consequently, the device provides an ideal solution for both Industrial-Scientific-Medical (ISM) and Wireless Local Area Network (WLAN) applications.

A NOVEL MINIATURE STRIPLINE FED ANTENNA WITH BAND-NOTCHED FUNCTION FOR UWB APPLICATIONS

A novel compact strip-line fed UWB antenna with band- notched characteristic is proposed. By employing a balanced antipodal structure and strip-line feed, the size of this antenna has been reduced to only 23mm £ 27:5mm with the dielectric substrate of relative permittivity 2.65. Meanwhile, a slot is added onto the radiating patch of the mid metalisation layer to realize the band-notched function, by tuning the length of which suitable rejected frequency band can be obtained. According to the measured results, the proposed antenna has a large bandwidth totally satisfying the requirement of UWB applications (3:1 » 10:6GHz) with good stable omnidirectional radiation patterns and gains except in the rejected frequency band (4:9 » 6:2GHz). Details of this antenna are described, and the experimental results of the constructed prototype are given, too.

Application of Hybrid FETD-FDTD Method in the Modeling and Analysis of Antennas

The stable hybrid finite-element time-domain-finite-difference time-domain (FETD-FDTD) method is applied for the numerical modeling and simulation of radiation from antennas. Use of unstructured tetrahedral elements in the modeling of antenna structure enables the application of the hybrid method to accurately model geometrically complex radiators. Traditional FDTD method with anisotropic perfectly matched layer (PML) is used to simulate unbounded media. Pyramidal elements are used in the transition from unstructured tetrahedral elements to structured hexahedral elements of the FDTD grid. The hybrid method is extended by using hierarchical mixed order basis functions in the unstructured region. The finite element formulation incorporates the excitation of antennas using coaxial line or stripline feed with transverse electromagnetic mode (TEM). Application of this method in the modeling of typical wideband antennas along with the results of input reflection coefficient and radiation pattern is presented.

Comments on "A Novel Broadband Printed Dipole Antenna With Low Cross-Polarization

The authors of [1] describe what they call a "double-layered" or stripline-fed version of Edward and Rees' printed dipole antenna [2]. Their claim of novelty for their stripline feed is not valid. To my knowledge, the first published description of this antenna was by D'Angelo etal. in 1996 [3].

Compact UWB monopole for multilayer applications

A novel compact, dual-layer UWB monopole antenna is presented. This low profile ultra-wideband antenna is fed by a 50 Ω shielded strip-line with an array of metal vias making the conducting walls. A printed disc monopole with a circular cut is the radiating element. The dual-layer, shielded strip-line feed allows for integration in multilayer technologies. The ultra-wideband, monopole characteristics of the antenna are confirmed experimentally.

Radiation efficient unidirectional low-profile slot antenna elements for X-band application

Slot apertures in metallic ground planes are very attractive candidates for conformal antenna applications. However, a low-profile unidirectional antenna requires a backreflector close to the slot aperture and the resulting stripline feed causes strong excitation of parallel-plate modes. In this paper, we investigate unidirectional reflector-backed slot configurations with parallel-plate mode suppression by shorting pins. Starting from a parametric study with respect to shorting pin location and backreflector distance, we present a stripline-fed rectangular slot element with radiation efficiency of more than 80%, a bandwidth of about 5% at a center frequency of 10 GHz. For increased bandwidth applications, a bow-tie slot element with about 8% bandwidth and radiation efficiency of close to 80% is proposed.

Radiation Efficient Unidirectional Low-Profile Slot Antenna Elements for X-Band Application

Abstract. Slots in metallic ground planes are very promising candidates for conformal antenna applications. However, a low-profile unidirectional antenna requires a back reflector close to the slot and the resulting stripline feed causes strong excitation of parallel-plate modes. In this contribution, we consider unidirectional reflector-backed slot configurations with parallel-plate mode suppression by shorting pins. Starting from a parametric study with respect to shorting pin location and back reflector distance, we present a stripline-fed rectangular slot element with radiation efficiency of more than 80% and a bandwidth of about 5% at centre frequency 10GHz. A careful optimisation of shorting pin locations guarantees reliable parallel-plate mode suppression without deteriorating the slot radiation behaviour. Coupling coefficients between parallel and aligned rectangular slot elements are presented. For increased bandwidth applications, a bow-tie slot element with about 8% bandwidth and radiation efficiency of close to 80% is proposed.

Wideband bow‐tie antenna with coplanar stripline feed

AbstractThe experimental investigation on a coplanar stripline‐fed bow‐tie antenna backed by an image plane is presented. Analysis of the radiation characteristics shows that the antenna exhibits an enhanced 2:1 SWR bandwidth of 46%, low cross polarization, and reduced back radiation. This antenna has applications in confocal microwave imaging and impulse ground‐penetrating radar. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 222–224, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20258

Design and analysis of TX/RX dual microstrip antenna using FDTD at Ku-band

A TX/RX dual microstrip 8×4 array antenna for satellite communication is designed, fabricated and measured and its element characteristics are analysed using finite difference time domain (FDTD). TX/RX frequency ranges are 14.0–14.5 GHz, 11.7–12.75 GHz, respectively, and vertical and horizontal polarisations are used for TX and RX. This antenna uses microstrip direct feeding for RX and aperture coupled stripline feeding for TX and accommodates stacked elements for a high directivity and wide impedance bandwidth. FDTD gives more accurate results because of the consideration of finite structure and imperfect two ground planes. This element has a return loss below −8 and −14 dB over the TX and RX frequency ranges and a gain of 7.5 and 8.3 dBi at the centre frequency of TX and RX. Return loss below −10 and −14 dB and a gain of 21.4 and 20.0 dBi were achieved for the TX and RX array, respectively.

Aperture-coupled dielectric resonator antenna using a strip-line feed

An aperture-coupled dielectric resonator antenna using a strip-line feed is investigated experimentally. As compared to the previous microstrip-line version, the new configuration eliminates the problems of backside radiation through the slot and frequency dispersion. The measured return loss, radiation patterns, and antenna gain of the new configuration are given in this letter. ©2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 120–121, 2000.

Stripline-fed printed square spiral slot antennafor circular polarisation

A novel design for a circularly-polarised printed square spiral slot antenna with a stripline feed is demonstrated. The printed slot antenna consists of a square spiral slot of /spl sim/1.25 turns, and a total slot length of approximately one free-space operating wavelength. By carefully trimming both ends of the square spiral slot, circular polarisation (CP) operation with a wide operating bandwidth can easily be achieved. A CP bandwidth of >6% has been obtained.

Analysis of stripline-fed slot-coupled patch antennas with vias for parallel-plate mode suppression

The paper presents an analysis of slot-coupled stripline-fed patch antennas with vias around the slot to minimize the power launched into the parallel-plate mode. A moment-method scattering formulation is invoked to include the effect of vias on the impedance characteristics of the antenna. Coupling between the stripline feed and the ground-plane slot is obtained by invoking reciprocity. Two design examples were fabricated and the measured input impedances verify the accuracy of the analysis. Vias considerably modify the impedance and resonant characteristics of a patch antenna. The radiation efficiency of patch antennas with and without vias is studied and proper location of the vias is shown to drastically reduce power in the parallel-plate mode.

Stripline-fed arbitrarily shaped printed-aperture antennas

A full-wave analysis method is presented for modeling the radiation properties of a stripline-fed planar printed-aperture antenna element. In this formulation, both the finite length of stripline and the finite aperture may be of any arbitrary shape since their equivalent electric and magnetic currents are modeled with triangular patch basis functions. Galerkin's method is applied to numerically solve the coupled mixed-potential integral equation (MPIE). Exact spatial-domain Green's functions are used to account for all radiation, surface-wave, and mutual-coupling effects. Interactions between the stripline feed and the radiating aperture are rigorously included. Numerical analysis is presented for the following nonrectangular shapes: an exponentially tapered slot, an annular slot, an annular slot with opposing stubs, and a monofilar Archimedean spiral slot element. Results are shown for input return loss, radiation patterns, and axial ratio for the circularly polarized elements.

Analysis of a strip in a waveguide

An analysis and an experimental study of a strip in a transverse plane of a rectangular waveguide below cutoff are presented. This work is a preliminary step in analyzing a stripline-fed slot antenna array in which each stripline feed is enclosed in a rectangular waveguide below cutoff. A numerical method is developed to solve a pseudo mixed-potential integral equation for the current on the strip excited by a delta-gap source at some point along the strip. The Green's function for dipole sources in the rectangular waveguide is used in the spectral and spatial representations and Shanks' transform is employed to speed up the convergence of the doubly infinite series. Numerical and experimental results are presented for a monopole fed at one wall of a rectangular waveguide and for a bottom-fed and bottom-loaded strip in a rectangular waveguide.

Integrated uniplanar transition for linearly tapered slot antenna

This paper presents the design, fabrication, and numerical modeling of two new uniplanar microstrip-to-coplanar strip (CPS) line transitions and a new variant of the linearly tapered slot antenna (LTSA). This new variant with an integrated uniplanar microstrip-to-coplanar strip line feed is called a V-LTSA. The advantages of these transitions in packaging and monolithic microwave integrated circuits (MMIC) integration are listed. The two transitions and the feed are modeled using finite difference time domain (FDTD) method. The overall agreement between the measured and modeled return-loss and insertion-loss characteristics of two back-to-back transitions is good. The resonance frequencies predicted by the FDTD method are within a few percentage points of the measurements. Furthermore, the V-LTSA with the feed is experimentally shown to have a wide return loss (/spl les/-10 dB) bandwidth, good radiation patterns, and low cross-polarization. The gain of the V-LTSA is 9 dB at the design frequency of 10 GHz. A proof-of-concept package to house the feed is experimentally evaluated and shown to have negligible effect on the antenna characteristics. This type of antenna readily integrates with MMIC packages in an array having a brick architecture. The V-LTSA has potential applications in phased arrays. >

Full-wave solution for an aperture-coupled patch fed by perpendicular coplanar strips

In recent years, the rectangular slot has been proposed as a means of power transfer between layers in multilayer printed antennas. Compared to probes, slots reduce fabrication complexity considerably, and allow more flexibility in the design of multilayer configurations. In the past, the aperture-coupled microstrip patch has been analyzed using the reciprocity theorem for the feeding line and the method of moments for the patch. The same method is used here for the analysis of an aperture-coupled patch fed by perpendicular coplanar strips. Theoretical results from this solution are compared with measurements for the input impedance of this antenna, and design data are given for the characteristic impedance of the coplanar strip feed line.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Mutual coupling between metal strip antennas on finite size, electrically thick dielectric substrates

An analysis of the mutual coupling between metal strip antennas which are contiguous with the ends of finite-size, electrically thick dielectric substrates is outlined. Such antennas have been proposed as useful monolithic microwave integrated circuit antennas for millimeter-wavelength applications. The analysis presented was verified experimentally, and the results are applied to three-element arrays of metal strip folded dipoles with coplanar strip feed lines. The effect of the electrically thick, finite-size dielectric substrates on the mutual coupling between elements of the arrays is described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Analysis of infinite arrays of substrate-supported metal strip antennas

An electric field integral equation method is applied to a metal strip antenna on an electrically thick dielectric substrate of finite size in a uniform infinite array environment. An efficient solution is found using the method of moments. Metal strip folded dipole antennas are analyzed both with and without a coplanar strip feed line, and the effects of the substrate and feed line are investigated. A technique for minimizing the effect of feed line scattering is presented, and arrays of these elements are shown to be capable of good scanning performance over a wide range of beam-steer angles. A phased array simulator experiment is described and the measured results show good agreement with those obtained by analysis. The class of antenna elements studied may be fabricated using monolithic microwave integrated circuit (MMIC) technology, and the analysis described illustrates the expected characteristics for millimeter-wavelength phased arrays of this type. >

Full-wave aperture coupled patch antenna

An aperture coupled patch antenna with a dual-lobed (cavity mode TM200) radiation pattern is described. The antenna employs a full-wavelength long patch fed via a butterfly-shaped aperture and a stripline feed network. This configuration provides high patch to feed network coupling and reduced back radiation. Measured return loss and pattern data are presented with proposals for several potential applications of this element.