RF identification device with near-field-coupled antenna
An embodiment of a RF identification device is formed by a tag and by a reader. The tag is formed by a processing circuit and a first antenna, which has the function both of transmitting and of receiving data. The reader is formed by a control circuit and by a second antenna, which has the function both of transmitting and of receiving data. The processing circuit is formed by a resonance capacitor, a modulator, a rectifier circuit, a charge-pump circuit and a detection circuit. The antenna of the tag and the processing circuit are integrated in a single structure in completely monolithic form. The first antenna has terminals connected to the input of the rectifier circuit, the output of which is connected to the charge-pump circuit. The charge-pump circuit has an output connected to the detection circuit.
1. An RF identification device, comprising;
a capacitor;
a first antenna disposed on a single die and having turns that surround an area of the single die;
a processing circuit including a detection circuit, a modulator and a rectifier stage, said modulator being arranged between said first antenna and said rectifier stage, wherein said rectifier stage comprises a positive rectifier and a negative rectifier;
wherein the single die is in completely monolithic form such that the processing circuit and the capacitor are disposed in the surrounded area; and
wherein said processing circuit further comprises a booster stage including a first booster circuit and a second booster circuit, wherein an input of said first booster circuit is electrically coupled to an output of said positive rectifier and an input of said second booster circuit is electrically coupled to an output of said negative rectifier.
2. The RF identification device according to claim 1 ,
wherein said processing circuit further comprises a first filter capacitor and a second filter capacitor;
said first filter capacitor having a first terminal coupled to the output of the positive rectifier and a second terminal coupled to a first terminal of said second filter capacitor; and
said second filter capacitor having a second terminal coupled to the output of the negative rectifier.
3. The RF identification device according to claim 1 , wherein said die comprises a substrate of semiconductor material overlaid by a dielectric layer, said first antenna being formed in a metallization layer formed inside said dielectric layer.
4. The RF identification device according to claim 3 , wherein said first antenna has a structure chosen between planar and stacked.
5. The RF identification device according to claim 4 ,
wherein said dielectric layer comprises a plurality of insulating layers separated by a plurality of mutually alternated metallization layers, said first antenna being formed in a top metallization layer, and said metallization layers being coupled together and to said antenna through vias.
6. The RF identification device according to claim 3 , wherein said dielectric layer comprises a ground shield of semiconductor material arranged in contact with said substrate.