Jorge Sosa-Pedroza

An UWB microstrip feeding quasi circular antenna

We present the analysis of a quasi circular planar antenna for UWB applications. Analysis includes comparison of coplanar and microstrip feeding. Evolution from the circular antenna requires modifications in the structure and ground plane to soften the edges obtaining improvements in the antenna parameters agreeing with the theory proposed by John Kraus. Evolution is performed for a circular antenna with a design frequency of 4.5 GHz with a bandwidth of approximately 20 GHz. The antenna feeding impedance is proposed as 50 ohms, built over a substrate of RF35-A 0.762 mm × 35 mm × 50 mm. The improvements obtained are reflected in the number of resonances of the antenna throughout the operating bandwidth.

A 9 slots antenna designed by Chebyshev technique and modeled by Finite Difference Time Domain

Slot antennas are widely used devices in microwave communications, especially when they are used as arrays, one of its applications are as WiFi antennas. We present the analysis of a slot antenna using the finite difference time domain method (FDTD). The FDTD method is an easy way to analyze complex structures; the theoretical analysis of a slot antenna supposes the slots are impressed over an infinite plane, missing the effect of the scattered fields in the waveguide sides, as the FDTD simulates the electromagnetic field, considering the media characteristics point by point, is possible to see its behavior in a more exactly way. The application example is a 9 element resonant array designed using the Chebyshev technique to reduce side lobes, antenna behavior was analyzed and then constructed; the results show a good agreement between both, simulation and experiment.

Equidistant and Non-Equidistant Sampling for Method of Moments Applied to Pocklington Equation

We present a non-equidistant sampling for the method of moments in the solution of Pocklington equation operator, to prove the reduction of segments junctions and conductor far end discontinuities. Comparison of equidistant and non-equidistant sampling is presented, obtaining E field over the surface of a lambda/2 dipole.

Size reduction of volcano monopole antenna for personal communication applications

We present a computer analysis of three different size reduction techniques on a volcano smoke planar antenna. A successfully structure size reduction was obtained using high permittivity substrates, partial cuts insertion, and slots insertion. We compare sizes of original antenna and the one modified, using reflection coefficient S11, gain and radiation patterns as analysis parameters. The original bandwidth of 5.14 GHz is achieved with gains up to 8 dB and almost omnidirectional radiation patterns. The final structure has dimensions of 45 × 100 × 1.52 mm, representing a 62% size reduction of original design.

Numerical approach to King’s analytical study for circular loop antenna

Abstract We exhibit a numerical technique based on the Pocklington equation and the method of moments for the study of circular loop antennas, and we show that the current distributions thus obtained are in total harmony with the corresponding analytical results of King [1].

Numerical and experimental analysis of a cross antenna

The cross antenna is a medium gain and circular polarization structure made of a conductor or strip line over a ground plane, following a cross contour of four or more branches. One end is feed by a generator and the other one is charged with a load impedance. This paper presents a theoretical and experimental analysis of an eight arms cross antenna, loaded with four different impedances. The theoretical study is made via the computational solution of Pocklingtons equation applied to the structure; experimental results are obtained over an antenna of a 12 AWG wire over a ground plane, working in 3.2 GHz. We present radiation efficiency, gain, field pattern, and axial rate results