ELECTRONICALLY STEP-BY-STEP ROTATED DIRECTIVE RADIATION BEAM ANTENNA

• US 3,846,799 A
• Filed: 08/13/1973
• Issued: 11/05/1974
• Est. Priority Date: 08/16/1972
• Status: Expired due to Term

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Michel Gueguen
• Inventors: Gueguen, Michel
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/387,837
• Time in Patent Office: 449 Days
• Field of Search: 343/701,833-837,846
• US Class Current: 343/833
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: H01Q 19/12 wherein the surfaces are concave H01Q19/18 takes precedence
• CPC Class Codes: H01Q 3/446 the radiating element being at the centre of one or more rings of auxiliary elements

Abstract

This invention relates to an electronically rotatable antenna which includes several radially arranged Yagi antennae having a common drive element. Reflector and director elements of each Yagi antenna are sequentially rendered operative by biasing suitable diodes short-circuiting them to a ground-plate. The radiation pattern is step-by-step rotated. Directivity is increased by short-circuiting other elements belonging to other arrays than the main one, those elements defining generatrices of a parabola having the driver element as a focus and the reflector element as an apex.

Claims

1. A directive radiation beam antenna of the type wherein said beam is rotated angularly in a step-by-step fashion comprising:

a plurality of S identical Yagi-type arrays having a common driven element, each of said plurality comprising;

one reflector parasitic element; and

a plurality p of director parasitic elements Dk where 1 <

OR = k <

OR = p;

wherein the array angularly ranked Q is derived from the array Q-1 by rotating it by an angle theta 360*/S around the axis of said common driven element;

a ground plane comprising a circular metal ground plate having a common axis with said common driven element, the S (1+p) parasitic elements having a height of approximately l/4 and arranged perpendicular to said ground plate;

a source of a bias signal;

a source of RF energy mounted between the base of said common driven element and said ground plate for feeding said common driven element;

a plurality of unidirectional current conducting elements each coupled to said ground plate, said source of bias signal and one of the S (1+p) parasitic elements, the impedance of each of said unidirectional elements being dependent upon said bias signal; and

a logic control device for controlling the step-by-step radiation beam rotation, said control device comprising;

an S-stage shift register having a clock frequency equivalent to S/ Tau , Tau being the time duration required for a 360* beam rotation; and

a plurality of pS three input OR-gates, each having outputs connected to the bias input of each unidirectional current conducting element associated with a director element, each of the S shift register outputs being provided with (1+3p) connections, the first coupled from the Qth stage to the bias input of the unidirectional element associated with the director element angularly ranked Q, p second ones coupled from the Qth stage output to the input of each of the OR-gates having outputs which control unidirectional elements associated with director elements angularly ranked Q, p third ones coupled from Qth stage output to the inputs of each of the p OR-gates whose outputs control the unidirectional elements associated with director elements of arrays angularly ranked (Q+Mk) or (Q+Mk-S) if (Q+Mk) is greater than S, and p fourth ones coupled from the Qth stage to the input of each of the OR-gates whose outputs control unidirectional elements associated with director elements of arrays angularly ranked (Q-Mk) or (Q-Mk+S) if (Q-Mk) is less than 0, where the k values of Mk are independent of Q and are determined by the polar coordinates of the closest director elements Dk of generatrices of a cylinder having a parabolic cross-section having as a focuse the base of the driven element and having as an apex the base of the reflector element of the associated array.

2. A directive radiation beam antenna according to claim 1 wherein unidirectional elements are PIN diodes having one terminal being connected to ground plate and the other terminal connected to the corresponding parasitic element base and to a choke inductance through which a suitable bias voltage is applied thereto.