Antenna

• US 7,629,942 B2
• Filed: 03/20/2007
• Issued: 12/08/2009
• Est. Priority Date: 04/14/2006
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kato, Noboru
• Primary Examiner(s): CHEN, SHIH CHAO
• Application Number:
  US11/688,290
• Publication Number:
  US 20080224935A1
• Time in Patent Office: 994 Days
• Field of Search: 343/702, 343/860, 343/862, 343/867, 343/895, 343/748
• US Class Current: 343/860
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/50 Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 5/40 Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
• 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
• CPC Class Codes: H01Q 9/27 Spiral antennas

Abstract

An antenna includes inductance elements that are magnetically coupled together, an LC series resonant circuit that includes one of the inductance elements capacitance elements, and an LC series resonant circuit that includes another of the inductance elements and capacitance elements. The plurality of LC series resonant circuits are used to radiate radio waves and are used as inductances of a matching circuit that matches an impedance when a power supply side is viewed from power supply terminals and a radiation impedance of free space.

Claims

1. An antenna comprising:

first and second power supply terminals; and

a plurality of resonant circuits;

a first LC series resonant circuit including a first inductance element and first and second capacitance elements that are electrically connected to both ends of the first inductance element; and

a second LC series resonant circuit including a second inductance element and third and fourth capacitance elements that are electrically connected to both ends of the second inductance element;

wherein

the first and second inductance elements are magnetically coupled together;

one end of the first inductance element is electrically connected to the first power supply terminal via the first capacitance element, and the other end is electrically connected to the second power supply terminal via the second capacitance element; and

one end of the second inductance element is electrically connected to the first power supply terminal via the third and first capacitance elements, and the other end is electrically connected to the second power supply terminal via the fourth and second capacitance elements.