The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 17, 2009
Filed:
Nov. 08, 2007
Hiroyuki Yamamoto, Kokubunji, JP;
Takanori Ninomiya, Hiratsuka, JP;
Kazuo Saitoh, Kodaira, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A signal line is drawn from a generally middle point of the antenna coil, and a capacitance-variable capacitors are connected at both sides of the antenna coil. This structure realizes a circuit in which a series resonance circuit composed of an antenna coil and a capacitor and an another series resonance circuit composed of an another antenna coil and an another capacitor are connected in parallel to each other across the generally middle point of the antenna coil to which the signal line is connected. Through the control of the resonance frequencies of the series resonance circuits, the parallel resonance frequency of the whole antenna is tuned to a desired frequency, and the resonance characteristic in which the impedance is matched to a specific value, e.g., 50 Ω, can be achieved.