There has been significant growth in the wireless market where new applications are accompanied with strict design goals such as low cost, low power dissipation and small form factor. Large capacity and range for new applications are the driving force for development of new standard such as third generation mobile system (3G). Recent research results show that the development that was not possible with current IC technology is made possible with MicroElectroMechanical Systems (MEMS) technology. Significant amount of research is taking place to replace the off-chip components with on-chip components to design a high performance receiver front end. The passive components such as switches, capacitors and inductors are integral part of RF front end. High quality (Q) inductors are used to design RF front-end components such as voltage-controlled oscillator (VCO) and low noise amplifier (LNA). However, they are the bottleneck in achieving the on-chip optimum components, because of Q factor dependence on parasitic effects, limiting the performance. In recent research publications different on-chip inductor structures such as coil, polygon, rectangular and stacked configurations have been suggested and used to implement high value of inductance. In this paper design and implementation issues of MEMS inductor are presented. The paper is divided in two sections, the first section presents the role of MEMS based passive components and second section presents design issues, implementation and analysis of different MEMS based inductors.
The new MEMS technology has made a major impact on design of RF components. The results that were not possible with current IC technology are made possible with MEMS technology. Researchers are working to replace the off-chip components with on-chip components so as to achieve a single chip receiver. The high Q inductors and capacitors required for designing RF components are the bottleneck in achieving the single chip receiver. The main advantage of direct conversion architecture is fewer components are required for implementations, but there are certain design issues that must be taken care for these implementations to be successfully achieved. In this paper, MEMS components used within RF systems is analysed. The VCO is the most difficult block of RF front-end design having large impact on system performance; so stringent requirements are imposed on VCO phase noise performance. A typical range of MEMS component values are used to design and implementation the VCO.
A control unit has been proposed, which is used to reconfigure a pipeline ADC for a mobile terminal receiver that can drastically reduce the power dissipation dependent on adjacent channel interference. The proposed design automatically scales the word length by monitoring the quantization noise along the in-band and out-of-bands powers in the UTRA-TDD spectrum. The new ADC performance was evaluated in a simulation UTRA-TDD environment because of the large near far problem caused by adjacent channel interference from adjacent mobiles and base stations. Results show that by using the control unit to reconfigure the ADC, up to 88% power dissipation could be saved, when compared to a fixed 16 bits ADC without the use of the control unit. This will prolong talk and standby time in a moble terminal.