Simulating Aperture Coupling of OAM Waves Through an Infinite PEC Plane Using EFIE-MoM—Part II: Application and Interpretation

In this second part of this contribution, the penetration of orbital angular momentum (OAM) waves through apertures is studied at 100 MHz to explore the effects on its behavior. OAM waves can have multiple OAM modes that are orthogonal in free space in terms of excitation and reception. Penetration of these waves through apertures is fundamental to many applications and can cause crosstalk within the OAM wave system and interference in systems beyond the aperture, leading to electromagnetic compatibility (EMC) problems. This article focuses on three aspects of aperture penetration: the influence of aperture shape, changes in the distance behavior of the OAM wave after penetration, and the effect of the OAM wave position and angle of arrival on the aperture. To isolate the effect of an aperture, simulating it in an infinite perfect electrically conducting (PEC) plane is necessary. Therefore, an appropriate algorithm was derived in Part I, where it was also discovered that OAM modes could penetrate apertures differently. Here, this algorithm will be used over 18 000 times to study aperture penetration. Apertures are shown to change the distance behavior of OAM modes. The symmetry of the channel between two arrays influences the crosstalk and can be used to predict the crosstalk.