A facility for UWB antenna measurements in time domain

Lestari, A.A.; Suksmono, Andriyan Bayu; Kurniawan, Adit; Bharata, E.; Yarovoy, Alexander; Ligthart, L.P.

doi:10.1109/iwat.2005.1461016

Cited by 17 publications

(9 citation statements)

References 2 publications

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“…A feed system using a TSR line has been introduced to feed a balanced antenna without balun [15], [16]. The TSR line employed here comprises two identical 50-Ohm semi-rigid coaxial lines soldered together along their length, resulting in a balanced transmission line with 100-Ohm characteristic impedance.…”

Section: Antenna Designmentioning

confidence: 99%

“…Imposing the boundary conditions at the wire end, we can express (12) as (13) where (14) (15) Since (13) holds for a single wire dipole, the maximum value of the resistor located at the end of the loading section can be approximated by (16) where is the number of wires in the loading section. The selected loading profile determines the amount of current at the end section of the antenna, which in turn determines the level of reflections occurring at the antenna end.…”

Section: Analytical Expression For Approximate Current Distributionmentioning

confidence: 99%

“…9. Measurements of input impedance and transmitted pulses were carried out using the technique introduced in [15] which employs a TSR line to feed the antenna, and in [16] which employs a UWB shielded loop antenna [21] as a probe, respectively. The antenna was fed with a TSR line which was connected to a generator exciting the pulse in Fig.…”

Section: Measurementsmentioning

confidence: 99%

“…The measurements were carried out in a non reflection-free room by paying attention to the distance from the antenna to the closest surrounding objects. The employed post-processing scheme of the measured data, which includes time windowing to exclude unwanted reflections from the surroundings and a deconvolution procedure to compensate for the probe's characteristics, is given in detail in [15] and [16]. The measured transmit waveform of the experimental antenna is plotted in Fig.…”

Section: Measurementsmentioning

confidence: 99%

See 3 more Smart Citations

A Modified Bow-Tie Antenna for Improved Pulse Radiation

Lestari

Bharata

Suksmono

et al. 2010

IEEE Trans. Antennas Propagat.

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The analysis, design, and realization of a modified bow-tie antenna optimized for impulse ground penetrating radar (GPR) applications is described. The proposed antenna shows improved properties important for GPR, which include its compact size (in comparison with a conventional bow-tie antenna) and ability to radiate UWB pulses with increased amplitude and very small late-time ringing. A substantial increase in the amplitude of the transmitted pulse is achieved by utilizing radiation from discontinuities introduced by the resistive loading employed in the antenna to suppress late-time ringing. By choosing an optimal distance between the antenna's feed point and the location of the resistive loading, radiations that occur from the antenna's feed point and the mentioned discontinuities at the resistive loading will combine constructively in the boreside direction of the antenna. As a result, one will observe a substantial increase of the amplitude of the transmitted pulse in the boreside direction. Furthermore, an analytical expression describing approximate time-harmonic current distribution is derived to indicate an optimal resistive loading profile for the proposed antenna. Additionally, the traveling-wave current distribution of the antenna is theoretically analyzed to examine the applicability of the obtained time-harmonic expression for pulse excitation. It has been found that when the antenna is resistively loaded both the time-harmonic and traveling-wave currents decay to approach nearly the same value at the end section of the antenna. As the amount of current at the antenna ends corresponds to the level of reflection which occurs there, the derived expression is found to be useful to indicate an optimal loading profile for the proposed antenna. A theoretical model of the proposed antenna has been developed to perform numerical analysis using a modified NEC-2 code. In addition, an experimental verification has been carried out and both the simulation and experiment confirmed the improved properties of the proposed antenna.

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Section: Antenna Designmentioning

confidence: 99%

Section: Analytical Expression For Approximate Current Distributionmentioning

confidence: 99%

Section: Measurementsmentioning

confidence: 99%

Section: Measurementsmentioning

confidence: 99%

See 2 more Smart Citations

A Modified Bow-Tie Antenna for Improved Pulse Radiation

Lestari

Bharata

Suksmono

et al. 2010

IEEE Trans. Antennas Propagat.

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“…The sand is placed in a wooden sandbox with dimensions of 150 x 30 x 46 cm. The dipole situated on the surface of the sand is fed with a twin semi-rigid (TSR) line [6] and connected to a vector network analyzer (VNA) as illustrated in the figure. The TSR line is employed to substitute a UWB balun which otherwise is needed.…”

Section: A Permittivity Ofsandmentioning

confidence: 99%

Dielectric Permittivity Measurement Based on Input Impedance Variations

Lestari

Wahyu

Yarovoy

et al. 2007

2007 Asia-Pacific Microwave Conference

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This paper presents a non-destructive method for measuring the permittivity of a relatively large dielectric material, based on the variation in the input impedance of a probe touching the surface of the material. In this work a wire dipole has been found suitable to be used as the probe. The method requires a theoretical model describing the variation of the resonance frequency of the dipole situated at the interface of a dielectric half-space. The model has been developed in this work using the method of moments. Dielectric permittivity is measured by placing the dipole on the surface of the material and by measuring the first resonance frequency in the input impedance of the dipole. The measured frequency is then compared with the theoretical model to determine the dielectric permittivity of the material. Measurement using another method which is more straightforward has been carried out to validate the proposed method. Good agreement between both methods has been observed.

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