Abstract
We expect a low cost and power saving dual-band WLAN chipset to be realized for the purpose of the needs of high speed wireless networking and wireless data communication. There are two band which WLAN operate in – 2.4GHz and 5.2 GHz. We employee the 0.35um SiGe BiCMOS technology to realize this chip with high integration, low cost, and good performance. We choose a novel concurrent dual-band architecture to realize this dual-band receiver. Low noise amplifier plays an important role in RF front-end circuits. Its performance influence the sensitivity of the whole receiver. We design the LNA with a well-adopt single stage cascode topology with emitter degeneration. We design the input and output matching network, minimum noise figure matching, and the optimum geometry and bias point of the SiGe HBTs to make the circuit work properly and simultaneously in these two bands of interest. Our simulation tool is ADS2002 provided by Agilent. We simulate with MEXTRAM 504 SiGe HBT model and other passive component model provided by TSMC. After fabricated by TSMC, this chip was stick on the PCB with wire-bonding. Then, we solder the passive component and SMA connector. We did the DC, RF, and noise measurement with this circuit. We compare this untuned circuit measurement results with the simulated results and try to find out the key point for RF circuit design. On the other way, we try to find the solution to improve the circuit performance. We successfully design and fabricate a dual-band LNA with SiGe BiCMOS technology even though its performance has shift in frequency domain. It can operate simultaneously at two bands. Most important, we got a lot valuable experiments in this design.