THE VELOCITY OF PROPAGATION OF ELECTROMAGNETIC WAVES

1955 ◽  
Vol 33 (6) ◽  
pp. 265-274 ◽  
Author(s):  
J. T. Henderson ◽  
A. G. Mungall
Keyword(s):  
Electromagnetic Waves ◽  
A Value ◽  
Velocity Of Propagation ◽  
Geodetic Surveying

Measurements of the velocity of propagation of electromagnetic waves have been carried out at a frequency of 400 Mc./sec., which is close to that employed for geodetic surveying in Canada. The results were consistent, giving a value for c of 299,780 km./sec. This value is probably low because the effect of discontinuities at the cavity junctions cannot be computed with certainty.

The velocity of propagation of electromagnetic waves derived from the resonant frequencies of a cylindrical cavity resonator

1950 ◽  
Vol 204 (1077) ◽  
pp. 260-277 ◽  
Keyword(s):  
Electromagnetic Waves ◽  
Correction Term ◽  
Wave Length ◽  
Cavity Resonator ◽  
End Effects ◽  
Steel Cylinder ◽  
A Value ◽  
Half Wave ◽  
Velocity Of Propagation ◽  
Cylindrical Cavity Resonator

The cavity resonator used in this investigation is a silver-plated steel cylinder 6.5 cm. in diameter and of adjustable length. Resonance in the H 011 mode is established at a frequency in the region of 9000 Mc./sec., and the length is then varied to give successive resonances at half wave-length intervals. The wave-length is thus determined and this, together with the frequency, the diameter and a correction term involving the sharpness of resonance, enables the velocity to be calculated. This procedure has some advantage over that used previously by Essen & Gordon-Smith in which the measurements were made with a resonator of fixed dimensions. The wave-length is determined only from differences in length, the first resonant length not being used, and in this way certain end-effects, such as those due to the coupling loops and to surface imperfections, are eliminated or greatly reduced. Moreover, by using different frequencies, or different modes at the same frequency, the diameter can be eliminated from the calculations and a value of c thus obtained in terms of frequency and length both of which can be measured with high precision. The result obtained is 299,792.5 ± 3 km./sec., and is thus in close agreement with that obtained by Essen & Gordon-Smith with a fixed cavity and also with the value of c determined recently by Bergstrand with an optical method.

scholarly journals Analysis of Total Electron Content (TEC) Near Real Time Using Dual Frequency GPS Data (Study Case: Surabaya)

2019 ◽  
Vol 94 ◽  
pp. 05005 ◽  
Author(s):  
Mokhamad Nur Cahyadi ◽  
Almas Nandityo Rahadyan ◽  
Buldan Muslim
Keyword(s):  
Total Electron Content ◽  
Electromagnetic Waves ◽  
Signal Propagation ◽  
Gps Data ◽  
Electron Content ◽  
Dual Frequency ◽  
Additional Time ◽  
Ionospheric Correction ◽  
Total Electron ◽  
A Value

Ionosphere is part of the atmospheric layer located between 50 to 1000 km above the earth's surface which consists of electrons that can influence the propagation of electromagnetic waves in the form of additional time in signal propagation, this depends on Total Electron Content (TEC) in the ionosphere and frequency GPS signal. In high positioning precision with GPS, the effect of the ionosphere must be estimated so that ionospheric correction can be determined to eliminate the influence of the ionosphere on GPS observation. Determination of ionospheric correction can be done by calculating the TEC value using dual frequency GPS data from reference stations or models. In making the TEC model, a polynomial function is used for certain hours. The processing results show that the maximum TEC value occurs at noon at 2:00 p.m. WIB for February 13, 2018 with a value of 35,510 TECU and the minimum TEC value occurs in the morning at 05.00 WIB for February 7, 2018 with a value of 2,138 TECU. The TEC model spatially shows the red color in the area of Surabaya and its surroundings for the highest TEC values during the day around 13.00 WIB to 16.00 WIB.

scholarly journals The velocity of propagation of electromagnetic waves derived from the resonant frequencies of a cylindrical cavity resonator

1948 ◽  
Vol 194 (1038) ◽  
pp. 348-361 ◽  
Keyword(s):  
Electromagnetic Waves ◽  
Cavity Resonator ◽  
Space Velocity ◽  
Maximum Error ◽  
Internal Diameter ◽  
Experimental Conditions ◽  
Resonant Frequencies ◽  
Half Wave ◽  
Velocity Of Propagation ◽  
Cylindrical Cavity Resonator

The frequency of resonance of an evacuated cavity resonator in the form of a right circular cylinder is given by the formula f = v 0 √[( r/πD ) 2 + ( n /2 L ) 2 ][1-1/2 Q ], in which v 0 is the free-space velocity of electromagnetic waves, D and L are the internal diameter and length respectively of the cylinder, r is a constant for a particular mode of resonance, n is the number of half-wave-lengths in the resonator and Q is the quality factor. Assuming the validity of this equation the value of v 0 can be obtained from measured values of f , D , L and Q . A copper cylinder of diameter approximately 7.4 cm. and length 8.5 cm. was constructed with the greatest uniformity of diameter and squareness of end-faces and its dimensions were measured. The resonant frequencies for a number of different modes were measured and experiments were made to show that the effects on frequency of the coupling probes to the oscillator and detector were negligibly small. It was concluded from these measurements that the most favourable experimental conditions can be obtained for the E 010 and E 011 modes. Final measurements on these gave v 0 = 299,792 km. /sec. The estimated maximum error of the result is 9 km. /sec. (3 parts in 10 5 ). This is the error of a single measurement and, since most of the errors are not necessarily random, little is gained by making a large number of measurements. The value is 16 km. /sec. greater than the recently determined values of the velocity of light, although the results are not in disagreement when the combined limits of accuracy are taken into account.

The asymptotic behaviour of a starting plume

1975 ◽  
Vol 72 (4) ◽  
pp. 753-771 ◽  
Author(s):  
Jason H. Middleton
Keyword(s):  
Asymptotic Behaviour ◽  
Vortex Ring ◽  
Similarity Solution ◽  
Ring Structure ◽  
Time Rate ◽  
A Value ◽  
Plume Velocity ◽  
Rate Of Increase ◽  
Velocity Of Propagation

A similarity solution is obtained for a model of the turbulent starting plume comprising a steady plume feeding mass, momentum and buoyancy into a vortex ring. Bulk equations representing the time rate of increase of ring momentum and ring buoyancy, together with equations (dependent on broad features of the ring structure) representing the velocity of propagation and time rate of circulation increase are used to determine the motion of the vortex ring. The similarity solution is found to exist only for diffuse distributions of vorticity and buoyancy within the ring. Further, the ratio of ring velocity to plume velocity, which is assumed to be constant, is found to take a value which agrees with that obtained from experimental observations.

BIREFRINGENCE IN CRYSTALS AND IN THE IONOSPHERE

1954 ◽  
Vol 32 (1) ◽  
pp. 16-34 ◽  
Author(s):  
C. H. M. Turner
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Electromagnetic Waves ◽  
Plane Waves ◽  
Diagonal Matrix ◽  
Effective Dielectric Constant ◽  
Normal Velocity ◽  
Electron Collisions ◽  
Velocity Of Propagation ◽  
The Magnetic Field

Propagation of plane electromagnetic waves in a homogeneous ionized gas in a uniform magnetic field is compared with the propagation of light in an optically inactive birefringent crystal. It is well known that propagation in a crystal may be described by using a system of real orthogonal axes for which the dielectric constant is given by a diagonal matrix. This paper shows that propagation of plane waves in the ionosphere may be described in a similar manner, the medium having an effective dielectric constant given by a diagonal matrix, provided that a system of "complex" orthogonal axes is used for the description of the components of the field vectors. This set of component axes (which is quite different from and not to be confused with coordinate axes) is equivalent to resolving the field vectors into components parallel to the magnetic field and two contrarotating circular components in a plane perpendicular to the magnetic field. An expression giving the velocity of each of the two modes of propagation in a given direction and expressions for the amplitude of each component of the field vectors are obtained (equations 43 and 44). Provided that one accepts the concept of a complex velocity of propagation, the results hold when electron collisions are included. When electron collisions are neglected, it is possible to form a double-sheeted surface, called the normal velocity surface, which is of some assistance in visualizing the manner in which the velocity of propagation of the plane waves in each mode changes with direction.

scholarly journals Excitation Analysis of Transverse Electric Mode Rectangular Waveguide

2020 ◽  
Vol 20 (1) ◽  
pp. 1
Author(s):  
M. Reza Hidayat ◽  
Mohamad Hamzah Zamzam ◽  
Salita Ulitia Prini
Keyword(s):  
Insertion Loss ◽  
Rectangular Waveguide ◽  
Electromagnetic Waves ◽  
Return Loss ◽  
Bandpass Filter ◽  
Frequency Range ◽  
A Value ◽  
Observation Process ◽  
Wireless Broadband ◽  
Loss Parameter

A waveguide is a transmission medium in the form of a pipe and is made from a single conductor. A waveguide has the function of delivering electromagnetic waves with a frequency of 300 MHz - 300 GHz and is able to direct the waves in a particular direction. In its development, a waveguide can be used as a filter. A filter consists of several circuits designed to pass signals that are generated at a specific frequency and attenuate undesired signals. One type of filter that can pass a signal in a particular frequency range and block signals that are not included in that frequency range is a bandpass filter. In this article, we study a rationing analysis on rectangular waveguide using TEmn mode followed by an implementation of a bandpass filter in the frequency range of 3.3-3.5 GHz for S-Band Wireless Broadband and Fixed Satellite. The observation process is done by shifting the position of the connector (power supply) as much as five times the shift to get the results as desired. Based on the analysis of the simulation process using Ansoft HFSS software, it is observed that the optimized results of the rectangular waveguide mode TE10 were obtained at a distance between connectors of 30 mm with a cut-off frequency of 3.3 GHz, the value of the return loss parameter of -34.442 dB and an insertion loss of -0.039 dB. Whereas, the optimized TE20 mode can be obtained at a distance of 70 mm between connectors, with a cut-off frequency of 3.5 GHz, the value of the return loss parameter of -28.718 dB and an insertion loss of -0.045. The measurement of TE10 mode in our Vector Network Analyzer (VNA) shows a cut-off frequency of 3.2 GHz, with a value of the return loss of -18.73 dB and an insertion loss of -2.70 dB. Meanwhile, a measurement of TE20 mode results in a cut-off frequency of 3.2 GHz, with a value of the return loss of -5.89 dB and an insertion loss of -4.31 dB.

scholarly journals Особенности распространения стоячих электромагнитных и электронных волн в металлическом проводнике с электрическим переменным током проводимости

2021 ◽  
Vol 57 (6) ◽  
pp. 72-78
Author(s):  
М. И. Баранов ◽  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electromagnetic Waves ◽  
Average Velocity ◽  
Axial Flow ◽  
Electromagnetic Energy ◽  
Azimuthal Magnetic Field ◽  
Metallic Conductor ◽  
Velocity Of Propagation ◽  
Basic Features

The paper demonstrates the results of approximate calculations on the establishment of basic features of the propagation of standing transversal electromagnetic waves (EMWs) and standing longitudinal de Broglie electronic waves in a homogeneous not massive non-magnetic metallic conductor of finite dimensions (the radius r0 and the length l0 >>r0) with the alternating axial-flow current of conductivity of i0(t) of different peak-temporal parameters. The correlation for the rated estimation of the average velocity of propagation of the standing transversal EMWs and standing longitudinal de Broglie electronic waves in a metal (alloy) of the indicated conductor is presented. It is shown that quantized standing transversal EMWs arising in a metallic conductor of finite dimensions substantially differ from ordinary transversal EMWs, propagated in the conducting environments of unlimited dimensions. An important feature of the standing transversal EMWs in the examined conductor is the fact that their tension of an axial-flow electric-field advances by a phase their tension of an azimuthal magnetic-field on the corner of π/2. It was established that in the standing transversal EMWs of the used conductor the energy of their electric field only passes into the energy of their magnetic field and vice versa. Therefore the standing transversal EMWs do not transfer the flows of the electromagnetic energy on the surface of the studied conductor.

scholarly journals Design and Realization of Circular Microstrip Antenna as Wifi Receiver Antenna Using Double Patch Array Method with Slot

2019 ◽  
Vol 3 (1) ◽  
pp. 21
Author(s):  
Ahmad Aulia'ur Rahman
Keyword(s):  
Microstrip Antenna ◽  
Electromagnetic Waves ◽  
Return Loss ◽  
Circular Array ◽  
Final Project ◽  
A Value ◽  
Circular Microstrip Antenna ◽  
Wifi Signal

<p><span>Wifi technology is a means to obtain information quickly, to strengthen the role of the signal, an antenna is needed because the antenna serves as a means for transmitting and receiving electromagnetic waves which are contained signal information. Mikrostrip antenna has a characteristic that is small, light, thin, easily fabricated, and can be used at a great distanceIn the use of wifi antenna require a relatively small shape and a cheaper prize. One of the antena on that specification is a microstrip antenna. By using 2 circular array method, the microstrip antenna can improve the wifi signal and wider on bandwidth. In this final project will be designed and created microstrip antenna with the 2 patches ccircular array methodwith slot that will be used as a wifi receiver. The results of the antenna microstrip rectangular 2 patches measurement indicating that it can work optimally on 2.406 GHz frequency, on a value of return loss – 22.90 dB, a value of VSWR 1.160, a value of bandwidth 0. 1035 GHz, and a value of gain 14.95 dBi.</span></p>

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