St-ericsson Sa

N.v. Nederlandsche Apparatenfabriek Nedap

Berend Hendrik Essink

Johannes Petrus Antonius Frambach

Hendrik Arend Visser

Sjoerd Martijn Herder

Maarten Jacobus Johannes Van Megen

Paul Jasper Compaijen

Reinbrand Gerhard Jaakob Frans Ottokar Johanan Van Lakwijk

A UHF RFID system is disclosed in which an RFID transponder or tag can be simultaneously powered and interrogated by multiple RFID transceivers. The architecture of the system is such that each transceiver generates its own carrier wave, with a frequency that might be equal to or different from the other units, and the interrogation data is distributed throughout a network of transceivers and modulated by each transceiver unit onto their own carrier waves. During an interrogation period, one or more of the transceivers will be configured as the master unit, generating and distributing the protocols commands. The other units can be configured as transmitters, receivers or transceivers. After each period the units may be given different roles. The proposed setup yields a system with the capability to power and interrogate RFID tags with multiple readers, without compromising the required modulation depth and protocol handling.

System of RFID reader units transmitting synchronized modulation using asynchronous carrier waves

A triple winding balun is combined with multiple switch assemblies to implement an antenna switch that provides good isolation, low loss, and good linearity with only a minor increase to the overall chip footprint. The antenna switch also isolates the receiver from power surges, where the power surges may be due to electrostatic discharge, undesirable WiMAX/LTE signals, etc. An exemplary antenna switch comprises a triple winding balun, a first switch subassembly, and an optional second switch subassembly. During stand-by and transmit modes, the first and second switch subassemblies respectively isolate the receiver from transmitter output current and connect a positive voltage bias to the third winding to prevent negative voltage swings at the receiver. During the receive mode, the configuration of the first and second switch subassemblies flips to connect the receiver to the third winding of the balun and to isolate the receiver from power surges.

Antenna switch with ESD isolation

A symmetrical, balanced, down-conversion mixer is achieved by the coordinated layout of a balanced Local Oscillator (LO) divider circuit and a balanced Radio Frequency (RF) mixer circuit, such that the LO divider is in the center and the RF mixer is arrayed symmetrically around the LO divider. In particular, the LO divider is partitioned into four portions (e.g., Ip, In, Qp, Qn), which are placed in respective quadrants, defined by orthogonal reference axes through the LO divider center. The RF mixer is similarly partitioned into four corresponding portions, which are placed around the LO divider portions in each quadrant. By integrating the LO divider and RF mixer in the layout of the symmetric, balanced, down-conversion mixer, greater component matching and control of current paths are possible, improving operational quality parameters such as IRR, IP, and LO feedthrough.

Mixer divider layout

Growing community of inventors

Varsseveld, Netherlands

Berend Hendrik Essink