hfss中的三种辐射边界比较.doc

Tips: HFSS 中的三种辐射边界 Radiation Boundary ? Mimics continued propagation beyond boundary plane – Absorption achieved via 2nd order radiation boundary – Absorbs best when incident energy flow is normal to surface – Distance from radiating structure – Place at least ?/4 from strongly radiating structure – Place at least ?/10 from weakly radiating structure – Must be concave to all incident fields from within modeled space Boundary is ?/4 away from horn aperture in all directions 4-44 ? 2012 ANSYS, Inc. February 1, 2012 Release 14.0 ANSYS, Inc. Proprietary February 23, 2009 ? 2009 ANSYS, Inc. All rights reserved. Inventory #002593 Radiation Boundary: Incidence Angle Dependency Radiation boundary functions well for incident angles less than 25°-30° Radiation Boundar Radiation Boundary Poor absorption of radiation boundary affects radiation pattern 4-45 ? 2012 ANSYS, Inc. February 1, 2012 Release 14.0 ANSYS, Inc. Proprietary February 23, 2009 ? 2009 ANSYS, Inc. All rights reserved. Inventory #002593 Radiation Boundary’s Location ? Radiation Boundary separation distance – Example probe-fed circular patch – Varied distance between absorbing boundary condition (ABC) and antenna ? λ /20, λ /10, λ /8, λ /4, λ /2, 3 λ /4, λ – Examined impact on return loss and gain 0.2 dB variation ?/4 and ? cases within 13 MHz of each other (0.1%) 4-46 ? 2012 ANSYS, Inc. February 1, 2012 Release 14.0 ANSYS, Inc. Proprietary February 23, 2009 ? 2009 ANSYS, Inc. All rights reserved. Inventory #002593 Perfectly Matched Layer (PML) ? Perfectly Matched Layer – Fictitious lossy anisotropic material which fully absorbs electromagnetic fields – Two types of PML applications ? “PML objects accept free radiation” if PML terminates free space ? “PML objects continue guided waves” if PML terminates transmission line – Guidelines for assigning PML boundaries ? Use PML setup wizard for most cases ? Manually create a PML when base object is curved or inhomogeneous – Parameters to Define: ? Define PML Thic