Circuit Design Based On Bulk Acoustic Wave Resonator

With the development of communication technology,the fifth generation of mobile communication(5G)has been on the stage of history.This means that mobile communication devices have more stringent requirements for size and frequency,especially in the field of smart phones,which not only require small size and high integration,but also have extremely strict requirements for power consumption.A bulk acoustic wave(BAW)device is a device that uses MEMS technology to convert electrical signals into acoustic signals,which greatly reduces the size of the device.The thin film bulk acoustic resonator(FBAR)has small integrated size,high Q value,can withstand higher power,and is compatible with semiconductor processes such as CMOS,and can be used to design high-performance filters and high-performance Oscillators/Phase locked loop has become a research hotspot at home and abroad,but the domestic FBAR technology is still at an elementary level.This paper analyzes the equivalent model of FBAR's piezoelectric film characteristics,and uses the propagation characteristics of acoustic waves in the piezoelectric layer to extract the scattering curve and the external expansion to change the resonant frequency to optimize the resonator.In order to reduce the threshold and design time of filter design,the filter is designed by the generalized Chebyshev function synthesis method and an optimization scheme is proposed.For the application of FBAR's high-Q performance to oscillator design,a detailed design plan is proposed,and the oscillator's topology is analyzed in detail.In this paper,the specific research contents and results of the design of film bulk acoustic wave resonator,the comprehensive design of bulk acoustic wave filter,and the design of FBAR-based oscillator are as follows:1.Design and optimization of thin film bulk acoustic wave resonatorAccording to the acoustic wave propagation mode in FBAR,the transverse wave is extracted and reflected by the structure of the Frame frame to reduce the energy leakage of the resonant cavity and thereby increase the Q value.From the simulation structure,the increased Frame increases the Q value of the oscillator by 45.Use the apodization method to improve the parasitic of the resonator,design a 2.5GHz thin film bulk acoustic resonator,and pass the piezoelectric-electromagnetic and layout simulation and processing test.The method of extending LC outside FBAR is proposed to optimize the bandwidth of the resonator and the specific formula is derived.2.Generalized Chebyshev synthesis method to design a bulk acoustic wave filterThe filter response parameters are obtained by the generalized Chebyshev synthesis method,and the non-resonant node model is used to extract the BVD equivalent model of the resonant unit of the step filter,and the equivalent model is converted into a physical model with a thick resonance area.The sixth-order filter of Band25 downstream frequency band(1930MH?1995MHz)is designed by comprehensive method,and the filter response with out-of-band suppression greater than 40dB and return loss 12dB is obtained.In order to reduce the processing cost and processing difficulty,the external extended LC method of FBAR is applied to filter design.A Band3(1700MHz?1790MHz)seventh-order filter is obtained,but only four resonators are needed,and the return loss is greater than 20dB and the out-of-band suppression is greater than 39dB.3.Oscillator design based on FBARBy analyzing the source of phase noise of the oscillator,and using the push-pull structure,common-mode voltage bias PMOS differential pair,and op-amp feedback to assist starting,the class-C oscillator is optimized to improve the phase noise performance.The design is based on FBAR 2.5GHz push-pull class C oscillator.The phase noise of the oscillator excluding the auxiliary start structure is-120.8dBc/Hz@10kHz,the FoM is 232.7,and it is powered by a 1.5V power supply,and the total power consumption is 0.4mW.The total power consumption of the oscillator with auxiliary start is 0.57mW,and the FoM is 232.4 when the frequency is shifted by 10kHz.The main contribution of this thesis is to optimize the FBAR resonator and combine the integrated design of the BAW filter with the circuit and perform joint simulation verification,which provides theoretical support for subsequent researchers.