Transmission line antenna and utility meter using same

• US 5,847,683 A
• Filed: 10/28/1996
• Issued: 12/08/1998
• Est. Priority Date: 10/28/1996
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wolfe, deceased, Paul D., Phelps, III, William C.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US08/739,474
• Time in Patent Office: 771 Days
• Field of Search: 343/866, 343/867, 343/741, 343/742, 343/700 MS, 343/748, 343/752, 343/732, 343/868
• US Class Current: 343/866
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A transmission line antenna (10) comprises first and second ends (14 & 16). Each end has a mounting portion defining a mounting height and an overlapping portion (18 & 20) defining an overlapping width. The overlapping portions are formed by bringing the ends around the ring and past each other, and are electrically connected together. The antenna is interconnected to a circuit board having a circuit impedance, and the mounting height and overlapping width are configured such that the antenna impedance matches the circuit impedance.

Claims

1. A transmission line antenna for a device having a circuit impedance, comprising:

a ring of conductor having an antenna impedance and first and second ends, each of said ends having a mounting portion defining a mounting height and an overlapping portion defining an overlapping width between the first and second ends; and

wherein said mounting height and said overlapping portion are adjusted such that said antenna impedance matches said circuit impedance.

2. A transmission line antenna as defined by claim 1, wherein said overlapping portion of said first end is electrically joined with said overlapping portion of said second end.

3. A transmission line antenna as defined by claim 1, wherein said ring of conductor is substantially circularly shaped.

4. A transmission line antenna as defined by claim 1, wherein said ring of conductor is substantially square shaped.

5. A transmission line antenna as defined by claim 1, wherein said first end of said ring of conductor is a feed point, and said second end of said ring of conductor is electrically connected to a circuit ground.

6. A transmission line antenna as defined by claim 1, wherein said ring of conductor has a circumference, said circumference less said overlapping portion is a half wavelength.

7. A utility meter, comprising:

a circuit board having a circuit having a circuit impedance;

a ring of conductor, mounted on said circuit board, having an antenna impedance and first and second ends, each of said ends having a mounting portion defining a mounting height and an overlapping portion defining an overlapping width between the first and second ends and wherein said mounting height and said overlapping portion are adjusted such that said antenna impedance matches said circuit impedance.

8. A utility meter as defined by claim 7, wherein said overlapping portion of said first end is electrically joined with said overlapping portion of said second end.

9. A utility meter as defined by claim 8, wherein said ring of conductor is substantially circularly shaped.

10. A utility meter as defined by claim 8, wherein said first end of said ring of conductor is a feed point, and said second end of said ring of conductor is a ground point.

11. A utility meter as defined by claim 7, wherein said ring of conductor is substantially square shaped.

12. A utility meter as defined by claim 7, wherein said ring of conductor has a circumference, said circumference less said overlapping portion is a half wavelength.