Fully On-Chip High Q Inductors Based on Microtechnologies
K. Shah, N. Khalid, J. Singh, H.P. Le, J. Devlin, Z. Sauli
La Trobe University, AU
Keywords: inductor, MEMS, VCO, phase noise, Q factor, silicon-on-sapphire
Abstract:The fast growing demand of wireless communications for voice and data has driven recent efforts to dramatically increase the levels of integration in radio frequency (RF) transceivers. Passive components such as inductor play important role in designing front end components such as voltage controlled oscillator (VCO) and low noise amplifier (LNA). Designing an optimum on-chip inductor is a major bottleneck because of poor quality factor (Q) value due to parasitic effects and substrate losses. To explore possible solutions for this bottleneck silicon-on-sapphire (SOS) technology and Micro Electro Mechanical Systems (MEMS) technology are investigated in this paper. This paper presents design and optimisation of inductors designed using MEMS and SOS technology and compares their performance using a VCO as testbench. Results showed that the 1.5nH SOS inductor achieves Q factor of 111 at 4GHz frequency where as the 1.5nH MEMS inductor achieves Q factor of 45 at 3.5GHz frequency. The VCO employing SOS inductor achieves lower phase noise and 50% lower power consumption than the VCO employing the MEMS inductor.