Dual polarization frequency selective medium for diplexing two close bands at an incident angle

• US 6,054,967 A
• Filed: 04/29/1999
• Issued: 04/25/2000
• Est. Priority Date: 03/04/1997
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Wu, Te-Kao, Toland, Brent T.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US09/301,817
• Time in Patent Office: 362 Days
• Field of Search: 343/909, 343/700 MS, 343/753, 343/755, 343/756
• US Class Current: 343/909
• CPC Class Codes: H01Q 15/0026 said selective devices having a stacked geometry or having multiple layers
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism
• CPC Class Codes: H01Q 15/12 functioning also as polarisation filter polarisation converters H01Q15/242
• CPC Class Codes: H01Q 15/24 Polarising devices; Polarisation filters H01Q15/12, H01Q15/22 take precedence

Abstract

A frequency selective medium that is adapted to receive an incident electromagnetic radiation at an angle of incidence of about 45° has two arrays of conductive elements on opposite parallel surfaces (20, 22) of a dielectric substrate. In one embodiment, the conductive elements are cross-dipoles (6) each having a horizontal dipole (10) and a vertical dipole (8) of different lengths and widths. In another embodiment, the conductive elements comprise a plurality of conductive gridded rectangular loops (40). The frequency selective medium allows incident waves that are within a passband of transmit frequencies to transmit through the medium, and reflects waves at frequencies within a stopband adjacent the passband. In other embodiments, meanderline polarizers (28) are added to cross-dipole and gridded rectangular loop frequency selective media to circularly or dual-linearly polarize incident linearly polarized waves.

Claims

1. A frequency selective medium for receiving electromagnetic radiation signals incident at an off normal angle, transmitting signals of a predetermined frequency range and reflecting other frequency signals, said frequency selective medium comprising:

a dielectric substrate having first and second surfaces;

a plurality of first and second dipoles on each surface, the first dipoles having a first length and being configured in a first orientation, the second dipoles having a second length and being configured in a second orientation which is substantially perpendicular to the first orientation, the first and second dipoles on each surface being interspersed, the length of each first dipole being different than the length of the closest interspersed second dipole.

2. A frequency selective medium as in claim 1, wherein all the first dipoles are substantially equal in length;

and, all the second dipoles are substantially equal in length.