cocoaNEC is a Mac OS X application intended primarily for the design and modeling of antennas.
cocoaNEC is a Universal Binary Cocoa based application. It runs natively on both Intel based and PowerPC based Mac computers that use Mac OS X 10.4 (Tiger) or newer.
The application is free and it can be downloaded from the Download Now link.
What's new in cocoaNEC
The NEC TL card only models an ideal lossless transmission line. cocoaNEC now lets you use more realistic coax and twin-lead models by modeling a transmission line with the admittance matrix of a NEC NT (network) card. For modeling common mode current, the shield of a coax cable can also be included.