×

RF TRANSMITTER FOR ELECTRICALLY SHORT ANTENNA

  • US 20130137387A1
  • Filed: 11/21/2012
  • Published: 05/30/2013
  • Est. Priority Date: 11/25/2011
  • Status: Active Grant
First Claim
Patent Images

1. Transmitter with two antenna output terminals for connecting to corresponding antenna terminals of an electrically short antenna for transmission of an electromagnetic signal, the transmitter comprising a capacitive energy storage, an output stage and a switching circuit having an open state and a closed state, the capacitive energy storage being adapted to form with the antenna when connected thereto a resonance circuit with a resonance frequency and a quality factor, the output stage being adapted to provide an electric transmission signal to the resonance circuit, the switching circuit comprising a first transistor for switching between the open state and the closed state and being connected to an antenna output terminal through a capacitance formed by the capacitive energy storage such that the maximum signal voltage occurring across the switching circuit in its open state is lower than the maximum signal voltage occurring across the antenna output terminals, characterised in that the transmitter is adapted to temporarily alter the quality factor by changing the series resistance of the switching circuit in its closed state.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×