Method of transporting radio frequency power to energize radio frequency identification transponders

A method of transporting Radio Frequency (RF) energy to an RF transponder (RF tag, the RF tag comprising at least one tag antenna, a rectifying circuit connected to the tag antenna for receiving energy from the tag antenna, a tag energy store for storing the energy received from the rectifying circuit, tag electronics, and means for delivering energy from the tag energy store to the tag electronics, comprising the steps of:

• a) determining a list of a large plurality of different frequencies;
• b) transporting RF electromagnetic wave energy for a first time from a base station to the remote RF tag at a first frequency chosen from the list of large plurality of different frequencies;
• c) ceasing to transport RF energy during an off time t.sub.o, where the off time is less than a time where the tag loses one or more functions;
• d) repeating steps b) and c) using frequencies chosen in order from the list.

A base station for transporting Radio Frequency (RF) energy to an RF tag, the RF tag comprising at least one tag antenna, a rectifying circuit connected to the tag antenna for receiving energy from the tag antenna, a tag energy store for storing the energy received from the rectifying circuit, tag electronics, and means for delivering energy from the tag energy store to the tag electronics, comprising:

• an RF generator for sending RF signal;
• an RF amplifier/modulator for receiving the RF signal and for sending RF power to antenna;
• and
• a computer, the computer controlling the RF generator to change from a first frequency f.sub.1 to a second frequency f.sub.2, the computer controlling the RF amplifier/modulator to reduce power sent to the antenna during the entire time the RF generator is changing from f.sub.1 to f.sub.2, where the time during which the power is reduced is less than the time where the RF tag energy store is depleted so that the tag electronics do not function.

A system for transporting RF energy from a base station to one or more remote RF tags, comprising:

• an RF tag comprising at least one tag antenna, a rectifying circuit connected to the tag antenna for receiving energy from the tag antenna, a tag energy store for storing the energy received from the rectifying circuit, tag electronics, and means for delivering energy from the tag energy store to the tag electronics;
• and
• a base station comprising an RF generator, and RF amplifier/modulator for sending RF power to an antenna;
• and a computer, the computer controlling the RF generator to change from a first frequency f.sub.1 to a second frequency f.sub.2, the computer controlling the RF amplifier /modulator to reduce power sent to the antenna during the entire time the RF generator is changing from f.sub.1 to f.sub.2, where the time during which the power is reduced is less than the time where the RF tag loses one or more functions.

A base station for transporting Radio Frequency (RF) energy to an RF tag, the RF tag comprising at least one tag antenna, a rectifying circuit connected to the tag antenna for receiving energy from the tag antenna, a tag energy store for storing the energy received from the rectifying circuit, tag electronics, and means for delivering energy from the tag energy store to the tag electronics, comprising:

• an RF generator for sending an RF signal, where the RF generator comprises a first RF generator for generating a frequency f.sub.1, a second RF generator for generating a frequency f.sub.2, and an RF switch;
• an RF amplifier/modulator for receiving the RF signal and for sending RF power to an antenna;
• and
• a computer, the computer controlling the RF generator to change from the first frequency f.sub.1 to the second frequency f.sub.2 controlling the RF switch to switch the input of the RF amplifier/modulator from the output of the first RF generator to the output of the second RF generator, the computer controlling the RF amplifier/modulator to reduce power sent to the antenna during the entire time the RF generator is changing from f.sub.1 to f.sub.2, where the time during which the power is reduced less than the time where the RF tag loses one or more functions.

A bases station for transporting Radio Frequency (RF) energy to an RF tag, the RF tag comprising at least one tag antenna, a rectifying circuit connected to the tag antenna for receiving energy from the tag antenna, a tag energy store for storing the energy received from the rectifying circuit, tag electronics, and means for delivering energy from the tag energy store to the tag electronics, comprising:

• an RF generator for sending RF signal;
• an RF amplifier/modulator for receiving the RF signal and for sending RF power to an antenna;
• and
• a computer, the computer controlling the RF generator to change from a first frequency f.sub.1 to a second frequency f.sub.2, the computer controlling the RF amplifier/modulator to reduce power sent to the antenna during the entire time the RF generator is changing from f.sub.1 to f.sub.2, where the time during which the power is reduced is less than the time where RF tag loses one or more functions and the time during which the power is reduced is greater than a time when a sideband of f.sub.1 is generated, the sideband of f.sub.1 having a frequency and power forbidden by government regulation.

A base station for transporting Radio Frequency (RF) energy to an RF tag, the RF tag comprising at least one tag antenna, a rectifying circuit connected to the tag antenna for receiving energy from the tag antenna, a tag energy store for storing the energy received from the rectifying circuit, tag electronics, and means for delivering energy from the tag energy store to the tag electronics, comprising:

• an RF generator for sending an RF signal;
• an RF amplifier/modulator for receiving the RF signal for sending RF power to an antenna;
• and
• a computer, the computer controlling the RF generator to change from a first frequency f.sub.1 to a second frequency f.sub.2, the computer controlling the RF amplifier/modulator to reduce power sent to the antenna during the entire time the RF generator is changing from f.sub.1 to f.sub.2, where the time during which the power is reduced is less than the time where the RF tag loses one or more functions and the time during which the power is reduced is less than 400 milliseconds.