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:
Mar. 30, 2004
Filed:
Oct. 19, 2001
Kazushi Nishida, Osaka, JP;
Katsuya Fujii, Osaka, JP;
Ichiro Kameyama, Osaka, JP;
Toru Sakuragawa, Osaka, JP;
Hiroshi Fujinaka, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An antenna duplexer capable of optimally decreasing the insertion loss and the voltage standing wave ratio (VSWR) at a center frequency and its vicinity in the pass band in transmitter-band of the device. The output port of transmitter surface-acoustic-wave (SAW) filter ( ) is electrically connected with phase shift circuit ( ), to which receiver SAW filter ( ) is also electrically connected. The transmitter and receiver SAW filters have different pass bands and attenuate the other pass band with each other. Phase shift circuit ( ) shifts the phase of receiver SAW filter ( ) in the transmitter-band. In addition, phase shift circuit ( ) has the characteristic impedance in which the magnitude of the reflection coefficient at the center frequency in the transmitter-band of receiver SAW filter ( ) is to be not less than 0.8 and the phase angle of reflection coefficient at the center frequency in the transmitter-band of receiver SAW filter ( ) takes the range from 0° to 45°.