| 1. |
- Aldhubaib, F., et al.
(author)
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Aspect segmentation and feature selection of radar targets based on average probability of error
- 2010
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 4:10, s. 1654-1664
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Journal article (peer-reviewed)abstract
- Through statistical estimation by a non-parametric model, a fused polarimetric and resonant return from the radar target is modelled as a function of the target aspect angle. The outcome of this type of modelling is a set of non-parametric density estimates, which are then used to represent this target in a multi-dimensional probability space. These densities within this probability space can be well separated and therefore utilised to make decision rules to identify targets of interest. The return set to be modelled is the average power set associated with spectral bands centred on the target natural resonant frequencies. This return set is mapped into density set using a Gaussian kernel function; subsequently, the density set will be considered as the target radar feature set of interest. To decrease density overlapping between respective densities of different targets, a criterion based on the Bayesian error is employed; first, to bisect the aspect global range into smaller sectors, and second, to select discriminative features that can minimise the average probability of error between the targets respective features. The results show that two targets with similar resonant frequencies can be separated by the Bayesian error criterion based on the proposed features. A simple likelihood ratio test had more than 80% success down to 20 dB of signal-to-noise ratio.
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| 2. |
- Arshad, Farzana, et al.
(author)
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Compact beam-switchable antenna for mm-wave 5G handheld devices
- 2021
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In: IET Microwaves, Antennas & Propagation. - : WILEY. - 1751-8725 .- 1751-8733. ; 15:7, s. 778-787
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Journal article (peer-reviewed)abstract
- An electronically beam-steerable antenna (BSA) is envisioned. The presented BSA is a possible solution to overthrow the limitations inherent to phased antenna arrays. The design consists of a gap coupling inset feed rectangular patch (driven element) and 3 x 1 passive parasitic patches deployed on both sides of the driven patch. Prototype having 20 x 20 mm dimensions is printed on Rogers(R) RT/duroid(R)5870. Four switches are used to load the reactive impedance on parasitic patches, which in turn, change the phases of surface current on parasitic elements and the driven element. Based on the different ON and OFF configuration of switches in parasitic array elements, the main beam is steered along with different directions. The simulated results show that the design can operate between 26.8 and 30.3 GHz a wide impedance bandwidth |S-11|< -10 dB (12.5%) with a peak gain of 8.9 dBi and wide 3-dB scanning angle that is, -37 degrees to 156 degrees in the azimuth plane. The exhibited performance of BSA with favourable characteristics, such as wideband, adequate gain, wide-angle beam switching, and low profile renders the BSA a good candidate for 5G millimetre wave handheld devices. Moreover, to corroborate the performance, the design is fabricated, and experimental measurements were performed. Congruence is observed between the experimentally measured and computationally simulated results. The simulated results of spherical coverage analysis of BSA with the integration of smartphone form factor are also presented.
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| 3. |
- Baghchehsaraei, Zargham, et al.
(author)
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Waveguide-integrated MEMS-based phase shifter for phased array antenna
- 2014
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 8:4, s. 235-243
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Journal article (peer-reviewed)abstract
- This study investigates a new concept of waveguide-based W-band phase shifters for applications in phased array antennas. The phase shifters are based on a tuneable bilateral finline bandpass filter with 22 microelectromechanical system (MEMS) switching elements, integrated into a custom-made WR-12 waveguide with a replaceable section, whose performance is also investigated in this study. The individual phase states are selected by changing the configuration of the switches bridging the finline slot in specific positions; this leads to four discrete phase states with an insertion loss predicted by simulations better than 1 dB, and a phase shift span of about 270°. MEMS chips have been fabricated in fixed positions, on a pair of bonded 300 µm high-resistivity silicon substrates, to prove the principle, that is, they are not fully functional, but contain all actuation and biasing-line elements. The measured phase states are 0, 56, 189 and 256°, resulting in an effective bit resolution of 1.78 bits of this nominal 2 bit phase shifter at 77 GHz. The measured insertion loss was significantly higher than the simulated value, which is assumed to be attributed to narrow-band design of the devices as the influences of fabrication and assembly tolerances are shown to be negligible from the measurement results.
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| 4. |
- Bondarik, Alexander, et al.
(author)
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Gridded parasitic patch stacked microstrip array antenna for 60 GHz band
- 2020
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:8, s. 712-717
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Journal article (peer-reviewed)abstract
- An array antenna design based on a gridded parasitic patch stacked microstrip antenna element is presented. The radiating part in the top layer of one antenna element has nine rectangular metal patches placed in a grid with three rows and three columns with a separation of 0.1 mm between the patches. Two means of realising the array are investigated. In a regular 2 × 2 concept, the parasitic patches of individual elements are placed next to each other, forming on the top layer a uniform grid of parasitic patches with six rows and six columns. In an alternative concept named as shared array, neighbouring antenna elements share one row and one column of parasitic patches, forming on the top layer a uniform grid of parasitic patches with five rows and five columns. The antenna arrays are designed for the 60 GHz band. The measured bandwidth is 13.8 GHz for the single antenna, 15.3 GHz for the 2 × 2 array, and 12.4 GHz for the shared array. The measured realised gain at 60 GHz is 6 dBi for the single antenna, 11 dBi for the 2 × 2 array, and 10.5 dBi for the shared array. The measured radiation patterns have good agreement with simulations.
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| 5. |
- Bosiljevac, M., et al.
(author)
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Construction of Green's functions of parallel plates with periodic texture with application to gap waveguides - A plane wave spectral domain approach
- 2010
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 4:11, s. 1799-1810
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Journal article (peer-reviewed)abstract
- This study presents Green's functions of parallel-plate structures, where one plate has a smooth conducting surface and the other an artificial surface realised by a one-dimensional or two-dimensional periodic metamaterial-type texture. The purpose of the periodic texture is to provide cut-off of the lowest order parallel-plate modes, thereby forcing electromagnetic energy to follow conducting ridges or strips, that is, to form a gap waveguide as recently introduced. The Green's functions are constructed by using the appropriate homogenised ideal or asymptotic boundary conditions in the plane-wave spectral domain, thereby avoiding the complexity of the Floquet-mode expansions. In the special case of a single ridge or strip, an additional numerical search for propagation constants is needed and performed in order to satisfy the boundary condition on the considered ridge or strip in the spatial domain. The results reveal the dispersion characteristics of the quasi-transverse electromagnetic modes that propagate along the ridges or strips, including their lower and upper cut-off frequencies, as well as the theoretical decay of the modal field in the transverse cut-off direction. This lateral decay shows values of 50-100 dB per wavelength for realisable geometries, indicating that the gap waveguide modes are extremely confined. The analytical formulas for the location of the stopband of the lowest order parallel-plate modes obtained by small-argument approximation of the dispersion equation are also shown. To verify the proposed analysis approach, the results are compared with the results obtained with a general electromagnetic solver showing very good agreement.
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| 6. |
- Castañer, Manuel Sierra, et al.
(author)
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Guest editorial : EuCAP2021 special section
- 2022
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In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 16:6, s. 303-304
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Journal article (peer-reviewed)
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| 7. |
- Cheng, Shi, 1980-, et al.
(author)
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Internal multiple-input, multiple-output antenna arrays for wireless wide area network and wireless local area network operation in seamless full metal cover laptops
- 2014
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 8:2, s. 73-79
-
Journal article (peer-reviewed)abstract
- A concept for multiple-input, multiple-output antenna arrays, integrated in an ultrathin full metal cover laptop computer, is proposed. The antennas are for octa-band wireless wide area network (WWAN) and triple-band wireless localarea network (WLAN) operation. The proposed solution makes use of the gap between the metallic display lid and keyboard chassis to form notch and slot antenna arrays, thereby removing the need for additional protrusions or openings. Simulated aswell as measured performance is presented. The notch antenna array for WWAN exhibits wide impedance bandwidth, with more than 24 dB isolation from 690 MHz to 3 GHz, and a total efficiency better than −2.5 dB. The slot antenna array forWLAN shows more than 12 dB isolation and a total efficiency of more than −3 dB. Both arrays exhibit a very-low envelope correlation coefficient of less than 0.1 within their respective frequency bands.
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| 8. |
- Das, Goutam Kumar, et al.
(author)
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Gain-enhancement technique for wearable patch antenna using grounded metamaterial
- 2020
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 14:15, s. 2045-2052
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Journal article (peer-reviewed)abstract
- In this study, a metamaterial (MTM)-based high-gain compact-wearable antenna for 2.45 GHz industrial, scientific and medical radio band application has been proposed. To achieve the flexibility of the antenna, textile material felt fabric has been chosen as the substrate of the antenna as well as MTM. An omega (omega) like structure has been taken as MTM unit cell design. High value of permeability is utilised for the gain enhancement of the antenna. In addition, very low specific absorption rate (SAR) is obtained using the MTM which makes the proposed antenna suitable for the biomedical application. The proposed antenna has achieved about 3 dB gain enhancement along with SAR value of 0.405 W/kg (1 g tissue). The design has been optimised and the prototype with the optimised parameter has been fabricated and tested over the semi-solid phantom and human body. Further, the proposed antenna over different type of textile material has also been validated.
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| 9. |
- Fan, Wei, et al.
(author)
-
Guest Editorial: Metrology for 5G Technologies
- 2019
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 13:15, s. 2581-2583
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Journal article (other academic/artistic)
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| 10. |
- Fonseca, Nelson J. G., et al.
(author)
-
Compact parallel‐plate waveguide half‐Luneburg geodesic lensin the Ka‐band
- 2020
-
In: IET Microwaves, Antennas & Propagation. - : Wiley-Blackwell. - 1751-8725 .- 1751-8733.
-
Journal article (peer-reviewed)abstract
- A parallel-plate waveguide half-Luneburg geodesic lens is designed and experimentally validated in the Ka-band. The geodesic lens profile is modulated using spline functions to reduce its height, while the symmetry halving the lens enables reduction of its in-plane dimensions. This design provides high gain, equivalent to that of a full-Luneburg lens, over a reduced angular range of ±20° to ±30° in azimuth. The specific design reported here has a maximum realized gain of 23.3 dBi in measurement, compared with 23.8 dBi for a full-Luneburg lens twice the size of this design. Very wideband operation is demonstrated both in simulations and measurements. This design is of interest for applications having limited space like millimetre-wave systems on board cubesats and small satellites.
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| 11. |
- Ghaderi Aram, Morteza, 1988, et al.
(author)
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An ultra-wideband compact design for hyperthermia: Open ridged-waveguide antenna
- 2022
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 16:2-3, s. 137-152
-
Journal article (peer-reviewed)abstract
- Antennas are the building block of radiative hyperthermia (HT) applicators. This study proposes a compact UWB antenna specifically tailored to meet the requirements for deep HT array applicators. The proposed Open Ridged-Waveguide (ORWG) antenna, which is an adaptation of a double-ridged horn antenna, operates over the frequency band of 400-800 MHz. It was experimentally assessed as a single element. The quality metrics considered were reflection coefficient, penetration depth, effective field size (EFS), and mutual coupling. The design shows a 75.5% fractional bandwidth with a reflection coefficient measured to be below -10 dB from 367 up to 820 MHz. The EFS is greater than the physical dimensions of the 3-by-4 cm aperture. The mutual coupling between two adjacent elements in the array, measured in a flat phantom arrangement, is lower than -30 dB throughout the entire band. The antenna's performance was further tested in two deep HT scenarios in order to assess the mutual coupling and focussing abilities while in the array configuration. To this end, phased array applicators consisting of 10 and 16 ORWG antennas were simulated in CST, and the results are presented for a homogeneous cylindrical muscle phantom and a realistic patient model, respectively. The good agreement between the simulated and measured results suggests that the antenna can be successfully used for HT.
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| 12. |
- Ivanchenko, Igor, et al.
(author)
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Combined L–S-bands antenna module
- 2019
-
In: IET Microwaves, Antennas & Propagation. - : IET. - 1751-8725 .- 1751-8733. ; 13:5, s. 541-545
-
Journal article (peer-reviewed)abstract
- A combined L-S-band antenna module consists of four rectangular patch antennas, two of which operate at the frequencies of the first harmonics (L-band), and two others at the frequencies of the second harmonics (S-band). The module is intended for use in super heterodyne signal reception circuits, for example in studying the various non-linear phenomena. The results of this study are presented in terms of improving the performance of each antenna and minimising their mutual influence. The resonance frequencies of the L-band antenna differ by 50MHz. All the antennas radiate close to the zenith and their beamwidths in two principal planes are virtually the same. At the resonance frequencies, the reflection coefficient is S-11<-30dB for the transmitting antenna, and S-11<-20dB for the receiving antenna. The minimum allowable distance between the antennas is determined, at which their mutual influence can be neglected (S-12<-50dB).
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| 13. |
- Jacobsson, Per, 1977, et al.
(author)
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Gradient-based shape optimisation of conformal array antennas
- 2010
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 4:2, s. 200-209
-
Journal article (peer-reviewed)abstract
- We present and test a gradient-based shape optimisation method for the minimisation of the active reflection coefficient for conformal array antennas. The goal function is an average of the active reflection coefficient with respect to all antenna elements, a prespecified frequency interval, and a set of excitation modes. The sensitivity of the goal function with respect to changes of the antenna's shape is based on the continuum form of Maxwell's equations, which provides good flexibility for the choice of field solver. The sensitivity is formulated in terms of the field solution of the original antenna problem and a similar adjoint field problem, which gives the sensitivity for an arbitrary number of design parameters given the solution of Maxwell's equations. We test the optimisation method in two dimensions for array antennas that conform to a circular cylinder, where both uniform arrays and arrays that occupy a part of the cylinder's circumference are considered. For some cases, we find that it is feasible to reduce the active reflection coefficient for arrays that partially cover the circumference of the cylinder by means of end elements that differ from the bulk elements of the array. In general, substantial reductions in the active reflection coefficient can be achieved by relatively small shape changes of the antenna elements. For the test cases considered in this article, the optimisation method typically converges to an optimised design within 5-15 iterations.
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| 14. |
- Jamaly, Nima, 1979, et al.
(author)
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Effects of coupling and overspeeding on performance of predictor antenna systems in wireless moving relays
- 2019
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 13:3, s. 367-372
-
Journal article (peer-reviewed)abstract
- Using predictor antenna systems for modern wireless moving relays and base stations on top of vehicles such as buses, trains etc. proves to be a reliable approach for collecting channel state information to such fast moving nodes. Recently, it has been shown that coupling between different ports of a multiport antenna system used as a part of a predictor system can reduce the prediction performance. In this study, by integrating position and velocity vectors in the channel covariance matrix as seen at the antenna ports in a rich multipath environment, the authors quantify the impact of antenna coupling on prediction performance. Moreover, practically these predictor systems are designed for a certain target velocity. They further quantify the adverse effect of velocities, different from the target velocity, on prediction performance. In case open-circuit decoupling is necessary, the sensitivity of the predictor antenna system performance with respect to the accuracy of the input network parameters is disclosed.
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| 15. |
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| 16. |
- Karttunen, Aki, et al.
(author)
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Path loss models with distance-dependent weighted fitting and estimation of censored path loss data
- 2016
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 10:14, s. 1467-1474
-
Journal article (peer-reviewed)abstract
- Path loss models are the most fundamental part of wireless propagation channel models. Path loss is typically modelled as a (single-slope or multi-slope) power-law dependency on distance plus a log-normally distributed shadowing attenuation. Determination of the parameters of this model is usually done by fitting the model to results from measurements or ray tracing. The authors show that the typical least-square fitting to those data points is inherently biased to give the best fitting to the link distances that happen to have more evaluation points. A weighted fitting method is developed that emphasises the accuracy at the distance range that is consciously chosen by the user as most important for a system simulation. As a further important point that is typically not taken into account for path loss parameter extraction, the authors show that typically measurement data (but also ray tracing) is censored, i.e. path loss values above a certain threshold cannot be measured. The authors present examples of weighted fitting models, and models with and without the censored data, for 28 GHz channels in urban macrocells, and show that these effects have a significant impact on the extracted parameters and that the fitting accuracy can be improved with the presented methods.
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| 17. |
- Kildal, Per-Simon, 1951, et al.
(author)
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Design and experimental verification of ridge gap waveguides in bed of nails for parallel plate mode suppression
- 2011
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 5:3, s. 262-270
-
Journal article (peer-reviewed)abstract
- This study describes the design and experimental verification of the ridge gap waveguide, appearing in the gap between parallel metal plates. One of the plates has a texture in the form of a wave-guiding metal ridge surrounded by metal posts. The latter posts, referred to as a pin surface or bed of nails, are designed to give a stopband for the normal parallel-plate modes between 10 and 23 GHz. The hardware demonstrator includes two 90 bends and two capacitive coupled coaxial transitions enabling measurements with a vector network analyser (VNA). The measured results verify the large bandwidth and low losses of the quasi-transverse electromagnetic (TEM) mode propagating along the guiding ridge, and that 90 bends can be designed in the same way as for microstrip lines. The demonstrator is designed for use around 15 GHz. Still, the ridge gap waveguide is more advantageous for frequencies above 30 GHz, because it can be realised entirely from metal using milling or moulding, and there are no requirements for conducting joints between the two plates that otherwise is a problem when realising conventional hollow waveguides.
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| 18. |
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| 19. |
- Lai, Szhau, 1985, et al.
(author)
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Integrated wideband and low phase-noise signal source using two voltage-controlled oscillators and a mixer
- 2013
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 7:2, s. 123-130
-
Journal article (peer-reviewed)abstract
- This study presents a method to design a wideband signal source based on two voltage-controlled oscillators (VCOs) with different centre frequencies and a mixer. The principle is to combine three frequency bands to form one wide frequency range. The three bands consist of second harmonic bands from two VCOs and a mixer band that is generated by mixing the two fundamental signals of VCOs to bridge the frequency gap. Apart from the wide tuning range, an additional benefit of a mixer-based signal source is that the phase-noise increases ∼3 dB/octave, which is less than the theoretical limit (6 dB/octave) for a fundamental frequency VCO followed by a frequency multiplier or extraction of second harmonic signal from a VCO. A prototype of the proposed signal source implemented in indium gallium phosphide hetero junction bipolar transistor monolithic microwave integrated circuit technology demonstrates both wide frequency tuning range and a very low phase noise. It exhibits a tuning bandwidth extending from 11.8 to 16.7 GHz and the signal's phase noise varies between −91 and −103 dBc/Hz at 100 kHz offset frequency.
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| 20. |
- Li, JunLong, et al.
(author)
-
Compact broadband circularly-polarised antenna with a backed cavity for UHF RFID applications
- 2019
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 13:6, s. 789-795
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Journal article (peer-reviewed)abstract
- A compact broadband circularly-polarised (CP) antenna is designed with a novel method for universal ultra-high-frequency (UHF) radio-frequency identification (RFID) readers. It is composed of a compact ring-shaped patch which aims to decrease the size of the antenna. A quadrature 3 dB coupler placed below the ground plane creates 90 degrees phase differences to generate the CP radiation of the antenna. To improve the performance of the proposed antenna and minimise its size, the authors use a coupling feeding method, an FR4 dielectric slab, and a metal cavity. The coupled feeding is implemented to eliminate the mismatching between the long probe and the ring-shaped patch, and to improve the gain over the operating band. The introduction of an FR4 dielectric slab and a cavity can reduce the antenna size and improve the impedance matching and axial-ratio (AR) bandwidth. The antenna with a backed cavity can increase the front-to-back ratio remarkably and improve the CP performance further. The measured results show that the antenna with a low profile (0.45 lambda(0) x 0.45 lambda(0) x 0.06 lambda(0) at 915 MHz) has the impedance bandwidth of 30.2% (730-990 MHz) and 3 dB AR bandwidth of 24.2% (760-970 MHz). Both the impedance and the AR bandwidth cover the worldwide UHF RFID band.
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| 21. |
- Lindgren, Tore, et al.
(author)
-
Monte Carlo simulation of an radio frequency identification system with moving transponders using the partial element equivalent circuit method
- 2010
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 4:12, s. 2069-2076
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Journal article (peer-reviewed)abstract
- When designing an radio frequency identification system it is important to take both the position and the movement of the transponders into account. In this study, a simulation method that enables the description of a complete RFID system including moving and rotating transponders as well as a complex, industrial environment is presented. By using the partial element equivalent circuit method to calculate the magnetic field generated by the reader antenna and describing the transponders using a magnetic dipole, it is possible to use the Monte Carlo method to describe the dynamic behaviour of the complete system. The method is used in this study to describe the difference in performance between two different reader antennas and these results are also compared to measurements of similar systems operating in an industrial environment. The difference in performance between the two systems is similar in both the simulations and the measurements. A small discrepancy was seen between the results from the simulations and the measurements which is for the most part because of the limited read rate of the RFID systems used in the measurements.
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| 22. |
- Liu, Qi, et al.
(author)
-
Compact printed two dipole array antenna with a high front-back ratio for ultra-high-frequency radio-frequency identification handheld reader applications
- 2015
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 9:1, s. 73-78
-
Journal article (peer-reviewed)abstract
- A printed two-dipole array antenna with a high front-back ratio is proposed for ultra-high-frequency (UHF) radio-frequency identification handheld readers. The proposed antenna is a parasitic dual-element array with the ends of both elements folded back towards each other for additional coupling. The antenna features a compact size of 89 mm x 87 mm and works properly with satisfactory gain and total efficiency in the wide UHF band of 860-960 MHz. Furthermore, the front-to-back ratio of 15-26.8 dB, the peak gain of 3.7-4.4 dBi and the total efficiency of more than 80% in the Federal Communication Commission (FCC) band make the proposed antenna attain high performance in the FCC band.
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| 23. |
- Lui, Hoi-Shun, 1980, et al.
(author)
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Improved mutual coupling compensation in compact antenna arrays
- 2010
-
In: IET Microwaves, Antennas and Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 4:10, s. 1506-1516
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Journal article (peer-reviewed)abstract
- A new method for the characterisation of receiving mutual impedances of compact arrays with omnidirectional antenna elements is proposed. Based on a large number of incident waves coming from different directions, the new method is able to calculate the receiving mutual impedances of omni-directional antennas based on a system of equations that characterise the received terminal voltages at different incident wave directions. In the new method, the receiving mutual impedances of all the antenna elements are calculated together in a single equation with the scattering effect from all antenna elements in the array being taken into account. Compared to the previous methods for the characterisation of the receiving mutual impedances, the new method preserves the boundary conditions of the original electromagnetic problem and produces much more accurate results on receiving mutual impedances, especially for compact antenna arrays. Direction finding examples based on the new method demonstrate its superior performance over existing methods.
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| 24. |
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| 25. |
- Nilsson, Hans-Erik, et al.
(author)
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Evaluation of a printed patch antenna for robust microwave RFID tags
- 2007
-
In: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 1:3, s. 776-781
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Journal article (peer-reviewed)abstract
- Antennas in RFID tags have often been designed in a single layer with copper as conductor and plastic foils as substrate. There is currently a large interest in roll to roll production of RFID tags and silver based inks have been developed for use in printed RFID antennas. Silver ink based single layer antennas works well and is providing 70% to 80% of the reading range compared to copper solutions. However, more advanced antennas are needed to provide less sensitivity to the environment of RFID tags .i.e. need for placing tags on metal or near water. In this work we present a study of multilayered antennas so called patch antennas, for 2.45 GHz RFID tags. The advantage of the patch antenna is that it can be applied to any kind of material, reflecting or lossy material, and still provide good antenna function. However, the patch antenna efficiency is strongly dependent on the material used. For low cost RFID tags in logistics there is a need to manufacture the antenna as a part of the packaging process. In the current work we have investigated the possibility to manufacture printed patch antennas of common packaging materials.
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