Analysis and modelling of rampart line antennas

Abstract

A new, efficient, and accurate analytical model is introduced for estimating the beam direction of rampart line antennas with microstrip radiators that can change beam direction with feeding frequency. The model takes its origins from 1-D array theory, in which the bends represent the radiating elements, and the interconnecting lines represent the phase shifters. A mathematical expression accounting for the equivalent length of the bends for the correct estimation of the distance between the radiators is introduced. The model was tested for various substrate relative permittivity values ranging from 2.9 to 6.45. This model can be used for arbitrary rampart line configurations by providing the equivalent dipole direction, depending on the orientation of the bends. An alternative geometry was proposed to reduce the coupling between the parallel line segments. A prototype operating in a bandwidth of 1 GHz around 7.8 GHz was realized on a Rogers RO4350B high-frequency laminate with a thickness of 1.524 mm. Both the radiation pattern and the reflection coefficient were measured and show a good agreement with the proposed analytical model and commercial full-wave simulation tool results.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

On-Body V-Band Leaky-Wave Antenna for Navigation and Safety Applications

“…2. Conventional microstrip-based LWA [9], [13], [32][33][34] operate in the radiation zone due to spatial harmonic of n = −1 like the unit cell shown in Fig. 2(a).…”

“…Additionally, l ij represents the length of the line segment between the points i and j, which were indicated earlier. To have accurate length of line intervals, the model from [9] is chosen for analysis.…”

“…Consequently, there are two design constraints on the length of microstrip line intervals: 1) Equation ( 5), to construct a unit cell that has broadside radiation at f = f b . and 2) Equation (9), to construct a unit cell with best circular polarization performance at f = f b . Table I depicts the dimensions of the unit cell based on the theory discussed at f b = 23 GHz.…”

“…LWAs proposed in [3][4][5][6][7] travelling wave and usually employ a TE n0 or in certain cases TM 11 mode [8] for radiation. However, to reduce fabrication complexity, lower manufacturing costs, and to enable the creation of compact antennas, microstrip-based guiding media LWAs are an appealing solution [9][10][11][12][13]. Meandering microstrip LWAs radiate due to the discontinuities created at the edges which results in a net magnetic current responsible for radiation [13], [14].…”

Conformal and Flexible Leaky-Wave Combline/Rampart Hybrid Antenna Arrays

“…The UC is typically small and relatively straightforward to design, but it does face some limitations due to coupling between vertical elements when the period is made too small. Efforts have been made to model and limit this coupling in [30]. .…”