Rectenna

• US 9,837,857 B2
• Filed: 06/25/2013
• Issued: 12/05/2017
• Est. Priority Date: 06/29/2012
• Status: Expired due to Fees

• Current Assignee: IHI Aerospace Company Limited (IHI Corporation)
• Original Assignee: IHI Aerospace Company Limited (IHI Corporation)
• Inventors: Fujiwara, Eiichiro, Aoki, Masaru
• Primary Examiner(s): Kessie, Daniel
• Application Number:
  US13/926,876
• Publication Number:
  US 20140001876A1
• Time in Patent Office: 1,624 Days
• Field of Search: 4555501, 455561, 4555621
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/248 provided with an AC/DC converting device, e.g. rectennas
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas

Abstract

A rectenna includes an antenna configured to receive a radio wave, a rectifier circuit configured to rectify the radio wave received by the antenna, a transmission line connected to the antenna and the rectifier circuit, and a modulation input circuit including a variable capacitance element. The variable capacitance element is connected at one end to a portion of the transmission line between an antenna connecting portion at which the antenna is connected to the transmission line and a rectifier circuit connecting portion at which the rectifier circuit is connected to the transmission line, and is configured such that the capacitance thereof varies in accordance with the voltage of a modulated signal wave input to the other end of the variable capacitance element.

Claims

1. A rectenna comprising:

an antenna configured to receive a radio wave;

a rectifier circuit configured to rectify the radio wave received by the antenna, the rectifier circuit including a diode that is coupled to a filter, the filter being coupled to a DC output;

a transmission line connected to the antenna and the rectifier circuit; and

having a length equal to ¼

of a wavelength of a fundamental of the radio wave received by the antenna;

a modulation input circuit including a variable capacitance diode, the variable capacitance diode being connected at one end to a portion of the transmission line between an antenna connecting portion at which the antenna is connected to the transmission line and a rectifier circuit connecting portion at which the rectifier circuit is connected to the transmission line, and configured such that capacitance thereof varies in accordance with a voltage of a modulated signal wave input to the other end of the variable capacitance diode; and

a capacitor connected to the modulation input circuit between the variable capacitance diode and a resistor, the resistor being connected to the modulation input circuit,

wherein the variable capacitance diode has an anode directly connected to the transmission line thereby hindering a carrier wave on the transmission line from entering the modulation input circuit, which reduces loss of the carrier wave.