دانلود رایگان ترجمه مقاله فیلترهای میکروالکترومکانیکی HF با Q بالا (نشریه IEEE 2000) (ترجمه ارزان – نقره ای ⭐️⭐️)

فیلترهای میکروالکترومکانیکی HF با Q بالا

High-Q HF Microelectromechanical Filters

Abstract

IC-compatible microelectromechanical intermediate frequency filters using integrated resonators with Q’s in the thousands to achieve filter Q’s in the hundreds have been demonstrated using a polysilicon surface micromachining technology. These filters are composed of two clamped-clamped beam micromechanical resonators coupled by a soft flexural-mode mechanical spring. The center frequency of a given filter is determined by the resonance frequency of the constituent resonators, while the bandwidth is determined by the coupling spring dimensions and its location between the resonators. Quarter-wavelength coupling is required on this microscale to alleviate mass loading effects caused by similar resonator and coupler dimensions. Despite constraints arising from quarter-wavelength design, a range of percent bandwidths is still attainable by taking advantage of low-velocity spring attachment locations. A complete design procedure is presented in which electromechanical analogies are used to model the mechanical device via equivalent electrical circuits. Filter center frequencies around 8 MHz with Q’s from 40 to 450 (i.e., percent bandwidths from 0.23 to 2.5%), associated insertion losses less than 2 dB, and spurious-free dynamic ranges around 78 dB are demonstrated using low-velocity designs with input and output termination resistances of the order of 12 k/spl Omega/.

1 Introduction

THE MAJORITY of the high-Q bandpass filters commonly used in the radio frequency (RF) and intermediate frequency (IF) stages of heterodyning transceivers are realized using off-chip, mechanically resonant components, such as crystal filters and surface acoustic wave (SAW) devices. Due to higher quality factor Q, such technologies greatly outperform comparable filters implemented using transistor technologies, in insertion loss, percent bandwidth, and achievable rejection [1]–[4]. However, being off-chip components, these mechanical devices must interface with integrated electronics at the board level, and this constitutes an important bottleneck to miniaturization and performance of superheterodyne transceivers. For this reason, recent attempts to achieve single-chip transceivers for paging and cellular applications have utilized alternative architectures (e.g., direct-conversion [5], wideband-IF [6], or direct subsampling [7]), rather than superheterodyne, and so far, have often suffered in overall performance as a result.

فیلترهای میکروالکترومکانیکی HF با Q بالا

High-Q HF Microelectromechanical Filters