This dissertation provides a study on low power, low cost transceiver design for IEEE 802.15.4b/ZigBee applications. First, the transceiver architecture selection is addressed in Chapter 2. An overview of IEEE 802.15.4b PHY, and then the radio specifications that satisfy the standard are described in Chapter 3. From the radio specifications, the specifications for the sub-modules such as RF receiver, RF transmitter, and analog baseband section are assigned considering the low power and low cost aspects. These specifications are performed through the system simulation.
The two well-known LNA design optimization techniques: simultaneous noise and input matching (SNIM) and power constrained simultaneous noise and input matching (PCSINM) are analyzed in Chapter 4. The noise parameter expressions of the SNIM and PCSNIM techniques are newly introduced. The LNA design principles, the potential as a low power LNA, and the practical limitations are explained. As a demonstration for the proposed technique a very low power LNA following the PCSNIM design guidelines was fabricated in 0.18 $\mum$ CMOS technology. The measured results show good agreement with the theoretical analysis.
Chapter 5 describes a low power, low cost direct conversion transceiver for 915 MHz-band IEEE 802.15.4b/ZigBee standard. The transceiver contains all the building block from the LNA input to the channel select filter and variable gain amplifier output, including a VCO and frequency divider for LO generation. To minimize the power dissipation a single-ended low noise amplifier followed by a double passive mixer is adopted. In this design, a single to differential signal conversion scheme does not need any additional circuit leading to low power and small chip size. In the transmitter chain, the LO leakage due to the mismatches in the devices sizes can be suppressed by building a DC feedback correction circuit incorporated with the upconversion mixer.
Taking advantage of the low power design techniques in the Chapter 4 and Chapter 5, the low power RF direct conversion receiver/transmitter front-end for 2.4 GHz-band IEEE 802.15.4b/ZigBee applications is developed in Chapter 6. However, in the RF receiver front-end wise, the passive mixer is designed to operate in a current mode by introducing a low impedance at the output loading. By operating in the current mode, the linearity of passive mixer itself can be improved leading to improvement in the overall receiver linearity. In the RF transmitter front-end side, the passive upconversion mixer and a single-ended driver amplifier are also utilized to reduce the power dissipation of the whole transceiver.
