Low-complexity, low power UWB radios are required for low data rate short-range applications. FM-UWB is a constant-envelope UWB communication system using double FM: digital FSK followed by high modulation index analog FM to create a constant-envelope signal. The system is intended for low data rate (<; 250 kbps), short-range (<; 10 m) personal area network (PAN) systems. Due to its simple architecture and relaxed hardware specifications, FM-UWB radio has the potential for low power consumption which is illustrated using two circuit implementation examples.

Low-complexity, low power UWB radios are required for LDR short-range applications. Potential low power air interfaces candidates are impulse radio UWB and FM-UWB. FM-UWB is a constant-envelope UWB communication system using double FM: digital FSK followed by high modulation index analog FM to create a constant-envelope UWB signal. The system is intended for low data rate (< 100 kbps), short-range (< 10 m) personal area network systems. Due to its simple architecture, FM-UWB radio will be low cost and have low power consumption

In this paper, system level design techniques for companding baseband switched capacitor (SC) filters for WLAN applications are presented. With companding, no AGC is required in front of the filter. A filter prototype is designed for 802.11g receiver and simulation results show that, with careful design of the opamps, a total harmonic distortion of less than 0.5% can be achieved. A new type of companding ADCs along with the algorithm to achieve companding in ADCs is proposed. It is shown that companding by a factor of 4 reduces the power consumption of the SC filter by a factor close to 4 times for a given dynamic range whereas it directly results in 12 dB reduction in the dynamic range requirement of the following ADC.

In Haddad et al. (2004), we have shown that it is feasible to design filters with arbitrary waveform responses and therefore we propose an ultra-wideband pulse generator incorporating a filter with a Daubechies' impulse response (i.e. maximally flat over the desired frequency range). This pulse generator is co-designed with wideband antennas. An eight-order Pade approximation of its transfer function is selected to implement the FCC stipulated frequency spectrum. Subsequently, the orthonormal (Johns et al., 1989) form is adopted, which is intrinsically semi-optimized for dynamic range, has low sensitivity to component mismatch, high sparsity and whose coefficients can be physically implemented. Each coefficient in the state-space description of the orthonormal ladder filter is implemented at circuit level using a novel 2-stage gm cell employing negative feedback. Simulation results in IBM's CMOS 0.13mum technology show that this pulse generator requires a total current of 25mA from a 1.2V power supply. The frequency coverage of the simulated waveform is about 85% of the FCC mask

The range and impact of SiGe bipolar and BiCMOS technologies on wireless transceivers for portable telephony and data communications are surveyed. SiGe technology enables transceiver designs that compare favorably with competing technologies such as RF CMOS or III-Vs, with advantages in design cycle time and performance versus cost. As wireless devices continue to increase in complexity using conventional battery technology as the power source, the desire to reduce current consumption in future transceivers continues to favor SiGe technology. Examples are drawn from contemporary wireless communications ICs. The performance of on-chip passive components in silicon technologies are also reviewed in this paper. Greater understanding of the limitations of passive devices coupled with improved models for their performance are leading to circuits offering wider RF dynamic range at ever higher operating frequencies. The innovations in on-chip passive design and construction currently being pioneered in mixed-signal SiGe technologies are enabling circuits operating deep into millimeter-wave frequency bands (i.e., well above 30 GHz). In addition, sophisticated on-chip magnetic components combined with deep submicrometer SiGe active devices in a transceiver front end are envisioned that enable single-volt SiGe circuits, with even lower current consumption than is achievable today. Relevant examples from the recent literature are presented.

It is anticipated that the next generation of wireless systems will deliver voice and data services at carrier frequencies extending up to 6 GHz. The front-end circuits for these radios must be aggressively designed in order to deal with issues such as analog and digital compatibility, higher linearity imposed by broadband signal processing at IF, low supply voltage to minimize size, weight and power consumption, as well as operation in multiple frequency bands. The challenges and opportunities facing the designer of these radio frequency (RF) front-end IC's in silicon will be addressed in this paper from both the technological and circuit perspectives.