Input admittance of a biconical antenna with wide feed gap

1990 ◽  
Vol 38 (11) ◽  
pp. 1784-1790 ◽  
Author(s):  
S.A. Saoudy ◽  
M. Hamid
Keyword(s):  
Input Admittance ◽  
Biconical Antenna

scholarly journals Input Admittance, Directivity and Quality Factor of Biconical Antenna of Arbitrary Cone Angle

2021 ◽  
Author(s):  
Ramakrishna Janaswamy
Keyword(s):  
Quality Factor ◽  
Cone Angle ◽  
Analytical Formula ◽  
Wide Angle ◽  
Slowly Varying Function ◽  
Input Admittance ◽  
Arbitrary Length ◽  
Biconical Antenna ◽  
Arbitrary Cone ◽  
Analytical Expressions

New analytical expressions and numerical results for the quality factor and directivity as well as computationally convenient expressions for the input admittance of a symmetrical biconical antenna of arbitrary length $L$ and cone angle $\theta_0$ are presented. The quality factor for a wide-angle biconical antenna is shown to very closely approach the Chu's limit of $Q = (kL)^{-1}\{1+(kL)^{-2}\}$. Numerical calculations based on the analytical formula for antenna admittance confirm the conjecture that Foster's reactance theorem remains invalid even for perfectly conducting antennas. Furthermore, the variation of directivity of a wide-angle biconical antenna is a slowly varying function of its electrical length and is shown to depart significantly from that of a thin cylindrical dipole. <br>

scholarly journals Input Admittance, Directivity and Quality Factor of Biconical Antenna of Arbitrary Cone Angle

2021 ◽  
Author(s):  
Ramakrishna Janaswamy
Keyword(s):  
Quality Factor ◽  
Cone Angle ◽  
Analytical Formula ◽  
Wide Angle ◽  
Slowly Varying Function ◽  
Input Admittance ◽  
Arbitrary Length ◽  
Biconical Antenna ◽  
Arbitrary Cone ◽  
Analytical Expressions

New analytical expressions and numerical results for the quality factor and directivity as well as computationally convenient expressions for the input admittance of a symmetrical biconical antenna of arbitrary length $L$ and cone angle $\theta_0$ are presented. The quality factor for a wide-angle biconical antenna is shown to very closely approach the Chu's limit of $Q = (kL)^{-1}\{1+(kL)^{-2}\}$. Numerical calculations based on the analytical formula for antenna admittance confirm the conjecture that Foster's reactance theorem remains invalid even for perfectly conducting antennas. Furthermore, the variation of directivity of a wide-angle biconical antenna is a slowly varying function of its electrical length and is shown to depart significantly from that of a thin cylindrical dipole. <br>

Determination of Damping Factors Based on the Measured Frequency Responses of Power Transformer Windings. Part 2. Analysis of Measurement Results

2021 ◽  
Vol 2 (2) ◽  
pp. 22-28
Author(s):  
Vasily S. LARIN ◽  
◽  
Daniil A. MATVEEV ◽  
Keyword(s):  
Active Component ◽  
Power Transformer ◽  
Neutral Current ◽  
Response Analysis ◽  
Reactive Component ◽  
Input Admittance ◽  
Equivalent Scheme ◽  
Frequency Responses ◽  
Measurement Results ◽  
Transformer Winding

In the first part of the article, based on the results of theoretical studies performed for a simplified transformer winding equivalent scheme, it was shown that the damping factors can be estimated from the width of the resonant peaks of the frequency responses of the module and the reactive component of the voltage at the midpoint of the equivalent scheme, as well as the active component of the input admittance and neutral current of the considered resonant scheme. In this part of the article, the practical possibility of applying the obtained theoretical relations between the damping factors and the width of resonant peaks in relation to the frequency responses of power transformer windings is considered. The results of calculations of the damping factors at the two power transformers made by using the fitting of the free component of transient voltage and by determining the width of the resonance peaks of the active component of winding neutral current and the voltage transfer function, corresponding to intermediate points of the winding. It is shown that the evaluation of the values of the winding damping factors can be performed as a byproduct of transformer condition assessment by frequency response analysis (FRA).

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