Antenna input impedance: experimental confirmation and geological application

Calculations and measurements of the input impedance of horizontal dipole antennas close to the Earth have been carried out, and the results have been compared with those of other workers. Antenna impedance measurements over both very highly and very poorly conducting ground planes were found to be consistent with theoretical calculations. Finally, a series of measurements traversing an interface between basalt and weathered granodiorite, both covered with soil, indicated that antenna input-impedance measurements can be useful for geological field surveys.

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Calculation of antenna input impedance by TLM method

Electronics Letters ◽

10.1049/el:19951500 ◽

1995 ◽

Vol 31 (25) ◽

pp. 2138-2139

Author(s):

Y. Huang ◽

D. Mirshekar-Syahkal ◽

I.J. Dilworth

Keyword(s):

Input Impedance ◽

Tlm Method ◽

Antenna Input

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An experimental investigation into the control of antenna input impedance through cancellation of near field standing energy

1998 IEEE Aerospace Conference Proceedings (Cat. No.98TH8339) ◽

10.1109/aero.1998.685814 ◽

2002 ◽

Cited By ~ 1

Author(s):

C.A. Grimes ◽

J.L. Horn ◽

F. Tefiku ◽

R. Shahidain ◽

D.M. Grimes

Keyword(s):

Experimental Investigation ◽

Input Impedance ◽

Near Field ◽

Antenna Input

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An RF Electronically Controlled Impedance Tuning Network Design and Its Application to an Antenna Input Impedance Automatic Matching System

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/tmtt.2003.821909 ◽

2004 ◽

Vol 52 (2) ◽

pp. 489-497 ◽

Cited By ~ 127

Author(s):

J. deMingo ◽

A. Valdovinos ◽

A. Crespo ◽

D. Navarro ◽

P. Garcia

Keyword(s):

Network Design ◽

Input Impedance ◽

Automatic Matching ◽

Antenna Input

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In-phase rejection requirements for measuring respiratory input impedance

Journal of Applied Physiology ◽

10.1152/jappl.1984.56.3.804 ◽

1984 ◽

Vol 56 (3) ◽

pp. 804-809 ◽

Cited By ~ 23

Author(s):

R. Peslin ◽

P. Jardin ◽

C. Duvivier ◽

P. Begin

Keyword(s):

Pressure Difference ◽

Input Impedance ◽

Pressure Transducer ◽

Absolute Pressure ◽

Impedance Measurements ◽

Differential Pressure Transducer ◽

Rejection Ratio ◽

Respiratory Flow ◽

In Series ◽

The Subject

Respiratory flow is commonly obtained by measuring the pressure difference across a pneumotachograph. When respiratory input impedance is studied, that pressure difference may be very small with respect to the absolute pressure swings inside the pneumotachograph. Then the in-phase rejection of the differential pressure transducer is expected to markedly influence the accuracy of the data. The problem was investigated by computer simulation and by measurements on a mechanical analog of the respiratory system made of a resistance, an inertance, and a compliance arranged in series. Both studies demonstrated that comparatively small differences in the volumes of the chambers or in the lengths or diameters of the connecting tubes led to artifactual frequency dependence of resistance and serious misestimation of compliance and inertance. Errors were larger when the resistance of the pneumotachograph was smaller and the impedance of the subject larger. In practice, with usual pneumotachographs accurate impedance measurements require using the most symmetrical transducers presently available (common-mode rejection ratio of about 70 dB at 30 Hz).

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Potassium iodide cluster based superhalogens and superalkalis: Theoretical calculations and experimental confirmation

Chemical Physics Letters ◽

10.1016/j.cplett.2020.137094 ◽

2020 ◽

Vol 741 ◽

pp. 137094

Author(s):

Gao-Lei Hou ◽

Xue-Bin Wang

Keyword(s):

Potassium Iodide ◽

Theoretical Calculations ◽

Experimental Confirmation

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Investigating the Performance of Bi-Static GPR Antennas for Near-Surface Object Detection

Sensors ◽

10.3390/s19010170 ◽

2019 ◽

Vol 19 (1) ◽

pp. 170 ◽

Cited By ~ 4

Author(s):

Xianyang Gao ◽

Frank J. W. Podd ◽

Wouter Van Verre ◽

David J. Daniels ◽

Anthony J. Peyton

Keyword(s):

Ground Penetrating Radar ◽

Input Impedance ◽

Test Site ◽

Late Time ◽

Near Surface ◽

Object Depth ◽

Ground Penetrating ◽

Antenna Input ◽

Surface Object ◽

Bow Tie

Antennas are an important component in ground penetrating radar (GPR) systems. Although there has been much research reported on the design of individual antennas, there is less research reported on the design of the geometry of bi-static antennas. This paper considers the effects of key parameters in the setup of a GPR head consisting of a bi-static bow-tie pair to show the effect of these parameters on the GPR performance. The parameters investigated are the antenna separation, antenna height above the soil, and antenna input impedance. The investigation of the parameters was performed by simulation and measurements. It was found when the bi-static antennas were separated by 7 cm to 9 cm and were operated close to the soil (2 cm to 4 cm), the reflected signal from a near-surface object is relatively unaffected by height variation and object depth. An antenna input impedance of 250 Ω was chosen to feed the antennas to reduce the late-time ringing. Using these results, a new GPR system was designed and then evaluated at a test site near Benkovac, Croatia.

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