An Approximate Method for Calculating the Near-Field Mutual Coupling Between Line-of-Sight Antennas on Vehicles

Frid, Henrik; Holter, H.; Jonsson, B. L. G.

doi:10.1109/tap.2015.2447003

Cited by 23 publications

(7 citation statements)

References 19 publications

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“…We assume far‐field transmission from the emitter to the DF system. The complex‐valued frequency‐domain signal measured in receiver channel n is therefore given by Friis' transmission equation on the general form derived in, for example, Kerns (), Hansen and Yaghjian (), and Frid et al (). The signal received by antenna (or sub‐array) n with far‐field amplitude

{\overset{f}{true}}_{n} false(\overset{r}{true} false)

is thus given by

x_{n} false(ω false) = ((), 2 π j {\overset{f}{true}}_{n} false(- {\overset{R}{true}}_{n} false) \cdot {\overset{f}{true}}_{t} false({\overset{R}{true}}_{n} false) \frac{e^{- j false(ω false/ c false) R_{n}}}{false(ω false/ c false) R_{n}}) s false(ω false),

where

{\overset{f}{true}}_{t}

is the far‐field amplitude of the transmitter antenna and

{\overset{R}{true}}_{n}

is the distance vector from the transmitter antenna to receiver antenna n located at

{\overset{r}{true}}_{n}

.…”

Section: Methodsmentioning

confidence: 99%

“…As a result, new postprocessing methods for analyzing the installed EEPs data have recently emerged. In particular, it was shown in Frid et al () that the installed far‐field data can be used to estimate the isolation between antennas, whereby the risk for unintentional interference between multiple systems on the same platform can be assessed. Case studies have been used to investigate the accuracy of the computed installed far fields (Malmsträm et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Determining Direction‐of‐Arrival Accuracy for Installed Antennas by Postprocessing of Far‐Field Data

2019

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Direction-of-arrival (DoA) estimation accuracy can be degraded due to installation effects, such as platform reflections, diffraction from metal edges, and reflections and refraction in the radome. To analyze these effects, this paper starts with a definition of the term installation error related to DoA estimation. Thereafter, we present a postprocessing method, which can be used to determine the DoA estimation accuracy for installed antennas. By computing synthetic signals from the installed far-field data, it is possible to analyze the installation errors described above, in addition to analyzing array model errors. The method formulation is general, thus allowing generic array configurations, installation configurations, and direction-finding algorithms to be studied. The use of the presented method is demonstrated by a case study of a wideband four-quadrant array. In this case study, we investigate the installation errors due to a single-shell radome. Thereafter, the effects of platform reflections are also analyzed, for an antenna placement in the tail of a fighter aircraft. Simulation results are presented for both the monopulse and the MUltiple SIgnal Classification direction-finding algorithms.

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{\overset{f}{true}}_{n} false(\overset{r}{true} false)

is thus given by

x_{n} false(ω false) = ((), 2 π j {\overset{f}{true}}_{n} false(- {\overset{R}{true}}_{n} false) \cdot {\overset{f}{true}}_{t} false({\overset{R}{true}}_{n} false) \frac{e^{- j false(ω false/ c false) R_{n}}}{false(ω false/ c false) R_{n}}) s false(ω false),

where

{\overset{f}{true}}_{t}

is the far‐field amplitude of the transmitter antenna and

{\overset{R}{true}}_{n}

is the distance vector from the transmitter antenna to receiver antenna n located at

{\overset{r}{true}}_{n}

.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determining Direction‐of‐Arrival Accuracy for Installed Antennas by Postprocessing of Far‐Field Data

2019

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“…where k = ω/c is the free-space wavenumber. Following [24], it is convenient to choose the following normalization coefficients…”

Section: A Array Pattern As a Sum Of Embedded Element Patternsmentioning

confidence: 99%

Convex Optimization of Wideband Monopulse Arrays

Frid,

Hultin,

Jonsson

2024

IEEE Trans. Antennas Propagat.

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A convex optimization program is presented for wideband arrays. Constraints are imposed on the frequency variation of excitation coefficients to ensure that the optimal solution can be realized in a wideband active electronically scanned array (AESA). AESA implementation with true time delays (TTDs) and phase shifters are handled separately. We also discuss the general case of combining TTDs and phase shifters. Contrary to single-frequency optimization, the wideband optimization method presented here ensures that the computed excitation is optimal over a specified bandwidth. It is shown that there is a trade-off between instantaneous bandwidth and sidelobe level. The proposed method works for both narrow and wideband arrays, as illustrated with examples. In addition to regular arrays, the method is also applicable to monopulse arrays. The optimization program is implemented in terms of embedded element patterns to account and compensate for mutual coupling, radome and platform effects.

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“…Other factors that affect the mutual coupling are inter antenna separation and type and size of ground plane. An approximate method for calculating the mutual coupling between lines of sight antennas in vehicles is given in [21]. The work was mainly intended to derive a computationally efficient approximation for mutual coupling as the solution using numerical methods is time consuming and demands huge computational resources due to the very large electrical length of the platform.…”

Section: Introductionmentioning

confidence: 99%

Characterization Study of Mutual Coupling Between Monopole Antennas on Finite Ground Plane at Out of Band Resonant Frequencies

Martin¹,

Ray²,

Prasad³

2020

PIER C

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When multiple antennas, operating at different frequencies, are installed on a single platform where the typical inter antenna spacing is a few wavelengths at the lowest frequency, the mutual coupling between the antennas can be optimized by the suitable selection of frequencies and the separation of adjacent antennas. This paper characterizes the dependency of mutual coupling between monopoles on the frequency and separation of the radiating/interfering monopole as well as on the size and shape of the ground plane. The out of band (off-band) characteristics of the monopoles are studied, and the effect of frequency offset between the adjacent monopoles on off-band mutual coupling is summarized. The off-band mutual coupling is reduced by more than 15 dB when the adjacent antenna frequency is selected to be near the fourth harmonic. In the case of smaller ground planes, better isolation of more than 20 dB is possible at intermediate antenna spacing than at the edges. The effect on radiation pattern of an antenna by the proximity of nearby antennas is also studied. The operating frequency/resonant length of the nearby antenna and the inter antenna spacing are found to be the key factors causing variation in radiation pattern. Lower off-band interfering antenna of bigger size is found to have significant effect on radiation pattern at spacing less than 2λ. Analysis has been carried out using FEKO, whose findings are validated using another software HFSS and measurements.

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An Approximate Method for Calculating the Near-Field Mutual Coupling Between Line-of-Sight Antennas on Vehicles

Cited by 23 publications

References 19 publications

Determining Direction‐of‐Arrival Accuracy for Installed Antennas by Postprocessing of Far‐Field Data

Determining Direction‐of‐Arrival Accuracy for Installed Antennas by Postprocessing of Far‐Field Data

Convex Optimization of Wideband Monopulse Arrays

Characterization Study of Mutual Coupling Between Monopole Antennas on Finite Ground Plane at Out of Band Resonant Frequencies

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