Hertzian Magnetic Dipoles Model of a Quasi-isotropic radiation microstrip patch based Antenna-in-Package

Abstract

The Internet of Things applications require small wireless sensors with quasi isotropic radiation, so that their placement is orientation insensitive. This paper shows the design steps for a microstrip patch based quasi-isotropic Antenna-in-Package (AiP). The structure proposed is a hollow cube with six microstrip patch radiators, one on each of its faces. The cubes internal walls are metallized to not only act as ground planes for the microstrip patch antennas, but also provide the necessary shielding between the radiators and the future embedded electronics. Thus, the problem in hand is to find the optimal phases to be applied to each patch so that when all six are activated simultaneously, the obtained radiation pattern is quasi-isotropic. Given the complexity of the structure, a simplified model of Hertzian magnetic dipoles was used to determine the phase each patch was to be excited to achieve the closest to an isotropic radiator as possible. A measured gain variation of 6.5 dB has been achieved for the entire 3D sphere after fabrication of a prototype. Keywords-Antenna in package (AiP), quasi isotropic radiation, Hertzian magnetic dipoles, microstrip patch antenna. I.

Quasi-Isotropic Antenna-in-Package with a Shielded Core and Wide Circular Polarization Coverage

“…The proposed AiP is the result of optimizing the design presented in [2].Different from it, this new design exhibits right-hand CP in a wide portion of the far-field sphere. As shown in Fig.…”

“…In the first approach, the radiators were kept with no tilting on each face (α = 0 • ). Elements 1 to 4 are kept in phase while elements 5 and 6 are excited with 65 • , the optimum conditions found in [2]. This setup resulted in a quasi-isotropic coverage of 94.5%.…”

“…Nevertheless, this integration presents challenges for designers as proximity to electronics interferes with the radiating structures [1]. To overcome this, approaches for core shielding like that in [2] become highly relevant.…”