Abstract: A circularly polarized single point feed notch antenna functions on land, sea, air and space vehicles and communicates using a broad frequency range while maintaining stealth during installation on a fighter aircraft by demonstrating a low Radar Cross Section (RCS). The circularly polarized notch antenna (CPNA) employs a phase delay card polarizer to achieve circularly polarized radiation or reception. The CPNA couples non-planar conductive fins to opposing sides of a non-conducting polarizing member. The fins fashion a ninety degree longitudinal fold, tuning slots at one fin end for tuning the antenna, and bifurcated arms at an opposing end formed by a notch. The bifurcated fins possess curved edges running from a part exterior to a part interior and a recession on the fold beginning near the tuning notch(es) and running the fin length until the recession runs out when it meets the curved edge.

Abstract: The microstrip antenna includes a conductive ground plane and a number of conductive broken loops which extend from a first end to an opposed second end. The first ends of each of the broken loops are connected to a feedline conductor for transmitting and receiving signals. In addition, the second end of each broken loop is spaced apart from the respective first end of the broken loop to define the broken loop. Further, a layer of dielectric material, such as a printed circuit board, can be disposed between the ground plane and a plurality of broken loops. Thus, by appropriately selecting the respective lengths of the broken loops, the frequency range over which the microstrip antenna transmits and receives signals can be tuned. In addition, the microstrip antenna is relatively thin so as to be disposed flush with the surface of a mounting platform within a relatively shallow cavity.

Abstract: A log periodic antenna of simple, circuit board construction exhibits an average standing wave ratio of less than 2.0 over a broadband frequency characteristic.