Rotatable antenna and integral, shielded impedance matching network

• US 5,579,023 A
• Filed: 05/08/1995
• Issued: 11/26/1996
• Est. Priority Date: 05/08/1995
• Status: Expired due to Fees

• Current Assignee: Herbert R. Blaese
• Original Assignee: Herbert R. Blaese
• Inventors: Blaese, Herbert R.
• Primary Examiner(s): Wimer, Michael C.
• Application Number:
  US08/436,153
• Time in Patent Office: 568 Days
• Field of Search: 343/702, 343/900, 343/905, 343/906, 343/888, 343/715, 343/749, 343/850, 343/851, 343/860, 343/882
• US Class Current: 343/851
• CPC Class Codes: H01Q 1/084 Pivotable antennas
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use

Abstract

A rotatable antenna is disclosed in which a radiator and matching network comprise a contiguous electrically conductive spring wire. The matching network comprises a coil extending generally perpendicular to the radiator. A 50 ohm coaxial cable has its ground conductor electrically connected to an electrically conductive sleeve which overlies the coil while the main conductor of the coaxial cable is tapped to the coil so that the matching network substantially matches the radiator impedance to the transmission line impedance. The matching network is rotatable with respect to a mounting member so that the radiator becomes rotatable about an axis that is generally perpendicular to the radiator.

Claims

1. A rotatable antenna, which comprises:

a radiator having a distal end and a proximal end;

a matching network coupled to said proximal end of said radiator;

said matching network comprising a coil extending generally perpendicular to said radiator;

an electrically conductive sleeve overlying said coil;

a transmission line coupled to said electrically conductive sleeve and coil;

said transmission line comprising a main conductor and a ground conductor;

said main conductor being tapped to said coil and said ground conductor being electrically connected to said sleeve, whereby said matching network substantially matches the impedance of said radiator to the impedance of said transmission line;

a mounting member;

said matching network being rotatable with respect to said mounting member whereby said radiator is rotatable about an axis generally perpendicular to said radiator.

2. A rotatable antenna as defined by claim 1, in which said transmission line is a 50 ohm coaxial cable.

3. A rotatable antenna as defined by claim 1, including a plastic radiator housing, said radiator housing defining a bore for receiving said radiator.

4. A rotatable antenna as defined by claim 1, in which said radiator and matching network comprise a contiguous electrically conductive wire.

5. A rotatable antenna as defined by claim 1, including a non-conductive sleeve separating said matching network from said electrically conductive sleeve.

6. A rotatable antenna as defined by claim 1, in which said tapped coil is contiguous with said radiator and including a small coil, contiguous with said tapped coil, coupled to said tapped coil, said electrically conductive sleeve having a smaller sleeve portion for receiving said small coil;

said ground conductor, said small coil and said smaller sleeve being electrically connected to each other.

7. A rotatable antenna as defined by claim 1, in which said radiator is a one-half wavelength element suitable for a bandwidth between about 800 MHz and 1,000 MHz.

8. A rotatable antenna, which comprises:

a radiator having a distal end and a proximal end;

a plastic radiator housing, said radiator housing defining a bore receiving said radiator;

a matching network coupled to said proximal end of said radiator;

said matching network comprising a coil extending generally perpendicular to said radiator, said radiator and said coil comprising a contiguous electrically conductive wire;

an electrically conductive sleeve overlying said coil;

a non-conductive sleeve separating said coil from said electrically conductive sleeve;

a transmission line coupled to said electrically conductive sleeve and coil;

said transmission line comprising a main conductor and a ground conductor;

said main conductor being tapped to said coil and said ground conductor being electrically connected to said sleeve, whereby said matching network substantially matches the impedance of said radiator to the impedance of said transmission line;

a mounting member coupled to said matching network;

said matching network being rotatable with respect to said mounting member whereby said radiator is rotatable about an axis generally perpendicular to said radiator.

9. A rotatable antenna as defined by claim 8, in which said transmission line is a 50 ohm coaxial cable.

10. A rotatable antenna as defined by claim 8, including a small coil, contiguous with said tapped coil, coupled to said tapped coil, said electrically conductive sleeve having a smaller sleeve portion for receiving said small coil;

said ground conductor, said small coil and said smaller sleeve portion being electrically connected to each other.

11. A rotatable antenna as defined by claim 8, in which said radiator is a one-half wavelength element suitable for a bandwidth between about 800 MHz and 1000 MHz.