This paper describes the architecture, system analysis and implementation of world-wide regulation compliant UHF RFID reader transceiver for ISO 18000-6 multi-class tags in the ISM band 860 MHz-960 MHz. The presented considerations are based on a system analysis providing evaluation of the transceiver's building blocks parameters in accordance with the required characteristics of a complete RFID reader system, read range, data transmission rate, reading speed and power consumption. The Phase Noise, Noise Figure, Sensitivity, P1dB, Dynamic Range are estimated for the design of a custom 'system-in-package' transceiver, implemented in LTCC-module. Based on the direct-conversion architecture, the reader transceiver integrates RFblocks, frequency synthesizer, modulation and demodulation functions, low frequency analog baseband. The receiver sensitivity is down to -85 dBm, the transmitter produces output power of +17 dBm.