UWB transmitter for communication and localization for IEEE 802.15.4a standard

This paper describes a monolithic integrated transmitter intended for impulse-radio (IR) Ultra-wide Band (UWB) applications compliant to the IEEE 802.15.4a standard. The transmitter operates in the higher UWB band on the communication channels #5, #6, #8 and mandatory channel #9. The impulse generation is based on the gated oscillator principle allowing required on-off keying (OOK) as well as binary phase shift keying (BPSK) with the pulse repetition frequency up to 499.2 MHz. The transmitter key components are optimized for the low power operation. The frequency synthesizer includes the novel low-power load-independent voltage controlled oscillator with a resonator isolated from the external load. Additionally, the programmable frequency divider based on the novel fast low-power triple-modulus prescalers is implemented. The triple- modulus prescaler realizes three modes (N/N±1) via the phase switching between the output signals of the master/slave ECL divide-by-two stage. In addition, the 50% duty cycle baseband clock of 499.2 MHz is derived from the divider chain, regardless of the chosen channel. Each functional transmitter block includes a “power down” switch for power efficient operation. Besides the communication, the time-of-arrival unit is implemented. It supports precise indoor localization in conjunction with an appropriate UWB receiver. The presented transmitter was fabricated in a 0.25 μm SiGe:C BiCMOS technology occupying a Si area of 1.85 × 1.85 mm².