## Electrical and Computer Engineering ETDs

#### Title

The Fundamental Resonant Frequency and Radiation Characteristics of Wide Angle Conical Antennas

#### Publication Date

2-8-2011

#### Abstract

Of recent interest for simple compact pulse power systems is the self-resonant wide-angle conical antenna. In its typical application, this antenna will radiate a transient damped sine wave pulse whose center frequency is the fundamental resonant frequency of the antenna. In order to properly design such an antenna, it is important to know the dependence of the fundamental resonant frequency on both slant height and half cone angle. Theoretical analysis of this type of antenna is typically based on the mode theory of antennas (as derived by S.A. Schelkunoff) in which the structure is treated as a conical transmission line. The theory is quite complicated and leads to two sets of equations involving infinite sums which must be solved simultaneously; this is a difficult task. In this effort, the accuracy of simplifications to the theory in predicting the fundamental resonant frequency of a wide angle conical antenna was explored by comparing the results obtained based on these approximations to experimental results as well as the results of numerical simulation using CST Microwave Studio. Good agreement is obtained between the simulated and experimentally measured results. It was found that a first order approximation to the theory as derived by C. Papas and R. King, while otherwise very useful, is insufficient to predict the fundamental resonant frequency of a wide angle conical antenna with reasonable accuracy; however, a second order approximation as derived by P.D.P. Smith does yield results that are in good agreement with results of experiment and simulation. It was found that the relationship between slant height (\u2113) and wavelength (λ) at the fundamental resonant frequency, for wide half cone angles, corresponds more closely to \u2113= λ /8 than the expected \u2113= λ /4. Of primary interest was the fundamental resonant frequency as a function of slant height and half cone angle; however, the peak radiated electric field and the radiation efficiency of the conical antenna as a function of half cone angle was also explored.

#### Keywords

wide angle conical antennas, fundamental resonant frequency

#### Document Type

Thesis

#### Language

English

#### Degree Name

Electrical Engineering

#### Level of Degree

Masters

#### Department Name

Electrical and Computer Engineering

#### First Advisor

Christodoulou, Christos

#### First Committee Member (Chair)

Christodoulou, Christos

#### Second Committee Member

Baum, Carl E.

#### Third Committee Member

Schamiloglu, Edl

#### Recommended Citation

Lawrance, Julie E.. "The Fundamental Resonant Frequency and Radiation Characteristics of Wide Angle Conical Antennas." (2011). http://digitalrepository.unm.edu/ece_etds/152