Gogoi, R.Raghuram, Antennas and Propagation Society International Symposium, ,Volume:2, 21-26July1996 Pages:962 - 965 vol.2 Electromagnetic Fields in Human Body Due To VLF Transmitter, Ronold W. Wheeler, Antennas and Propagation, IEEE Transactions on, Volume: 6, Issue:1, Jan1958 Pages:120 - 122 Analysis of VLF Loop Antennas on the Earth Surface for Underground Mine Communication, A.K. IEEE ,Volume: 2, 16-21 June 2002 Pages:264 - 267 vol.2 Fundamental Relations in the Design of a VLF Transmitting Antenna, Harold A. Belrose, Antennas and Propagation Society International Symposium, 2002. A Multiple Tuned Multiple FED Broadband MF Antenna, John S. ,8th IEEE, 14- Pages:330 - 334 Multiple Tuned VLF Antennas, Manfred Schopp, IEEE Transactions on Broadcasting, Vol. Tietsworth, Instrumentation and Measurement Technology Conference, Record. 1990 IEEE, 30Sept.-3Oct.1990 Pages:1091 - 1096 vol.3 A New System For Measurement of Low Frequency Radio Transmitting Antenna Parameters in Near Real Time, Steven C. MILCOM '90, Conference Record, 'A New Era'. Watt, Pergamon Press, 1967 High Power Very Low Frequency/Low Frequency Transmitting Antennas, Peder Hansen, Military Communications Conference, 1990. References VLF Radio Engineering, Arthur D. Pictures Cutler, Maine Antenna Installation Pictures Simplified VLF Transmitting Antenna Some Other Applications Water resource exploration. VLF Loop antenna can be used for this purpose.Middle East Technical University May 2004 Normal radio frequency get attenuated rapidly so VLF Band is used.
Provide wireless communication between earths surface and miner. Some Applications of VLF Antenna (II)Underground Mine Communication: Especially it is designed for the event of mine disaster. Transmitted wave will be attenuated in the sea-water so output power must be high enough to reach receiver. Propagation in sea water is almost vertical so only electric and magnetic type of dipoles can be used.
#Vlf receiver antenna design skin#
Some Applications of VLF Antenna (I)Submarine: Requires EM Wave at VLF because of skin effect. Goliath Antenna Middle East Technical University May 2004 Tuning and retuning after the system is disturbed is difficult.Each antenna has to be matched to a transmitter.Middle East Technical University May 2004 The effective ground loss with multiple-tuning will be less than for a single element. Instead of one and vulnerable antenna, several and smaller elements can achieve the same bandwidth-efficiency product.If one element is shunt off servicing, the others still can be operated. Radiation resistance and efficiency are increased. Multiple Tuned VLF Antennas (II) Ground losses are reduced. Several small multiple-tuned elements can be used. Multiple Tuned VLF Antennas (I)To have sufficient bandwidths: Huge antenna systems can be built.
#Vlf receiver antenna design series#
Q: the circuit reactance resistance ratio X/R0R0: Total series resistance Vertical Electric Monopole Antenna -Antenna BandwidthThe 3 dB bandwidth b in (c/s) for a single resonant circuit is:f : resonant frequency Vertical Electric Monopole Antenna -Radiation Efficiencywhere and antenna loss resistanceĮffective power = (power capacity of the transmitter) x (antenna system efficiency)Middle East Technical University May 2004 Vertical Electric Monopole Antenna -Equivalent Antenna Circuit. The vertical electric field in terms of radiated power is: Vertical Electric Monopole Antenna -Radiated Power. Vertical Electric Monopole Antenna -E and H FieldsAssume a uniform vertical electric current I along a monopole of effective height he Vertical Electric Monopole Antenna -Antenna Model. High power levels are needed for transmission. Designing an efficient transmitting antenna is difficult. Problems with VLF Antennas Bandwidth is less than 200 Hz. The principal objective is to radiate specified amount of power over a sufficient bandwidth of frequency.Middle East Technical University May 2004 Generally cover areas of up to a square kilometer or more. Generally have a number of towers 200-300 m high. High background noise levels.Communication needs large amount of power at the output of the transmitter. Appropriate for long range communication. VLF Band EM waves penetrate well in the sea water.Low atmospheric attenuation.
Increased demand for very reliable long range communication and navigation systems caused to use of VLF band. VLF BandQuestion: Why do we use VLF Band? Answer: VLF (Very Low Frequency) Band take place from 3 kHz to 30 kHz in the frequency spectrum. Middle East Technical University May 2004Ĭontent VLF Band VLF Antennas About VLF Antennas Advantages and Disadvantages of VLF Antennas Example : Vertical Electric Monopole Antenna Multiple Tuned VLF Antennas Some Applications on VLF Antennas
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