Bandpass frequency selective surface

• US 5,384,575 A
• Filed: 09/26/1988
• Issued: 01/24/1995
• Est. Priority Date: 09/26/1988
• Status: Expired due to Fees

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Wu, Te-Kao
• Primary Examiner(s): Cain, David C.
• Application Number:
  US07/249,039
• Time in Patent Office: 2,311 Days
• Field of Search: 343/909, 343/911 R, 343/753
• US Class Current: 343/909
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective

Abstract

An improved bandpass frequency selective surface is disclosed which provides a wide pass band and reflection band with low loss at varying angles of incidence, low cost, low volume and light weight. The improved bandpass frequency selective surface of the present invention includes a mesh-patch array 10 disposed on at least a portion of a surface wherein the mesh-patch array 10 includes a square grid 12 surrounding numerous squares 20, 21, 22 and 23. A specific teaching of the invention concerns the design of the elements of a mesh-patch array 10 such that the frequency selective surface transmits or reflects the desired microwave signals.

Claims

1. An improved frequency selective surface comprising:

a square grid composed of a first plurality of lines of material having a first conductivity perpendicularly intersecting a second plurality of lines of material having said first conductivity so as to provide a plurality of square spaces therebetween, each of said plurality of lines having a spacing D, the distance from the beginning of a line of said first plurality of lines to the beginning of an adjacent line of said first plurality of lines and the distance from the beginning of a line of said second plurality of lines to the beginning of an adjacent line of said second plurality of lines being equal to P and the width of said lines of said first plurality of lines and the width of said lines of said second plurality of lines being equal to W;

a plurality of squares of material having said first conductivity wherein each square of said plurality of squares is disposed within an associated square space of said plurality of square spaces and the distance between each edge of each square of said plurality of squares and the adjacent line of said first plurality of lines or the adjacent line of said second plurality of lines is g;

such that P is equal to 0.24 inches, g is equal to 0.022 inches, D is equal to 0.228 inches and W is equal to 0.012 inches and

a surface of material having a second conductivity, said square grid and said plurality of squares being disposed on at least a portion of said surface.

2. A mesh-patch array comprising:

a square grid composed of a first plurality of lines of material having a first conductivity perpendicularly intersecting a second plurality of lines of material having said first conductivity so as to provide a plurality of square spaces therebetween, each of said plurality of lines having a spacing D, the distance from the beginning of a line of said first plurality of lines to the beginning of an adjacent line of said first plurality of lines and the distance from the beginning of a line of said second plurality of lines to the beginning of an adjacent line of said second plurality of lines being equal to P and the width of said lines of said first plurality of lines and the width of said lines of said second plurality of lines being equal to W;

a plurality of squares of material having said first conductivity wherein each square of said plurality of squares is disposed within an associated square space of said plurality of square spaces and the distance between each edge of each square of said plurality of squares and the adjacent line of said first plurality of lines or the adjacent line of said second plurality lines is g,

the dimensions for the elements of the mesh-patch array being related as follows R=1/(1+Y²) and T=1-R, where T represents the equation of said microwave signal of said first frequency that will pass through said surface and R represents the equation of said microwave signal of said second frequency that will be reflected from said surface, Y=1/(2(X-1/B)), X=ω

L, B=ω

C, ω

=2π

f, f is the frequency of the applied microwave signal, L is the equivalent inductance of the array, C is the equivalent capacitance of the array, X=D/P(P/λ

(ln(csc(π

g/P)))), B=4D/P(P/λ

(ln(csc(π

W/2P)))), and λ

is the wavelength of the applied microwave signal.