SHIELDED END-FIRE ANTENNA

• US 3,757,345 A
• Filed: 04/08/1971
• Issued: 09/04/1973
• Est. Priority Date: 04/08/1971
• Status: Expired due to Term

• Current Assignee: Keith R. Carver
• Original Assignee: Keith R. Carver
• Inventors: Carver, Keith R.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Nussbaum, Marvin
• Application Number:
  US05/132,570
• Time in Patent Office: 880 Days
• Field of Search: 343/895,772,785-786
• US Class Current: 343/786
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 13/02 Waveguide horns

Abstract

The in ention is for an antenna comprising an end-fire radiator in a shielded structure. A specific case is an axial-mode helical antenna in a conical horn which produces a circularly polarized pencil beam with low sidelobe level over a 2-to-1 bandwidth with a gain in the order of four times that of a simple helix.

Claims

1. An antenna comprising an end-fire radiating antenna and a shielding structure surrounding said element, said shielding structure comprises a conical electromagnetic horn, said radiating antenna is an axial mode helical conductor, and wherein the parameters of said antenna are within the following range:

30* <

OR = phi o <

OR = 70*0.75 lambda <

OR = D <

OR = 5.00 lambda 0.75 lambda <

OR = Lc <

OR = 4.00 lambda 0.25 lambda <

OR = Ln <

OR = 4.00 lambda 1 <

OR = N <

OR = 16 10* <

OR = Alpha <

OR = 16*0.90 lambda <

OR = C <

OR = 1.10 lambda wherein lambda free-space wavelength at design frequency phi o included cone angle D mouth diameter Lc truncated cone altitude Ln total axial length of helix N number of helix turns Alpha helix pitch angle C circumference of imaginary cylinder on which helix is wound.

2. An antenna as set forth in claim 1 wherein said antenna has the following parameters:

phi * 45*D * 3 lambda Lc Lh 3 lambda N 10 Alpha 14*C lambda