Design, Realization, and Experimental Test of a Coaxial Exponential Transmission Line Adaptor for a Half-Impulse Radiating Antenna

Abstract

This paper describes the simulation, design, realization and experimental test of atapered transmission line for adapting a broadband impulse generator to a radiating antenna, for a frequency range of 50 MHz to 1 GHz. Two different taper geometries are considered and discussed in the analysis: exponential and logarithmic. Two analysis methods are also used: (1) analytical equations obtained by applying the transmission line theory, and (2) numerical simulations in both frequency-and time-domain using Comsol®. It is shown that in general an exponential taper performs better than a logarithmic one, especially at high frequencies. Time domain simulations reveals that for fast transient subnanosecond pulses, both tapers can be used equivalently and the signal does not suffer from any significant distortion while traveling along the tapers. We also show that analytical equations obtained using the transmission line theory are in very good agreement with full-wave simulation results and can be used advantageously in the design of tapers. The paper also presents the mechanical design and the realization of an exponential taper used for the connection of a 50-pulser to a Half Impulse Radiating Antenna (HIRA) having an input impedance Z A = 100 . The realized taper is fully characterized in frequency-domain using a vector analyzer and in time domain using a reflectometer and shown to be performing in agreement with the simulations.

A new method for analyzing non-uniform guiding structures

“…A few analytical methods are presented for the study of non-uniform TLs made by a particular profile, such as the TLs with the exponential 10 , linearly tapered 11 , and power-law 12 profiles. One classical method for analyzing a NUTL is segmenting the structure into a cascade of uniform sections 13 , 14 .…”

Analysis of a nonuniform guiding structure by the adaptive finite‐difference and singular value decomposition methods

“…Several analytical solutions have been introduced for analyzing specific cases, such as structures with exponential [10], linearly tapered [11], power-law [12], and Hermit [13] profiles. Except for the nonuniform structures with a few special profiles, no analytical modeling with the general profiles has been introduced.…”

Design and Implementation of an Integrated Switched-Oscillator Impulse Generator

“…In [10], an electromagnetic simulation in the frequency domain is employed to relate the parameters of a coaxial-transmission line-based switched oscillator to the properties of the radiated waveform. An improved, high power realization of such design is discussed in [11][12][13]. In this paper, the design, simulation, fabrication, and testing of a low-power integrated printed circuit board (PCB) switched oscillator is presented.…”

“…The proposed switched oscillator is fabricated using a coplanar waveguide (CPW) transmission line that allows the integration of the radiating antenna. A gas discharge tube has been used in this low-power design that plays the role of the switch in the switched oscillator and mitigates the issues involved with a spark gap used in the existing designs [11][12][13].…”