tailieunhanh - Crystalline Silicon Properties and Uses Part 14

Tham khảo tài liệu 'crystalline silicon properties and uses part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 314 Crystalline Silicon - Properties and Uses material will cause diaphragm to bend leading to a change of the air gap in the device and therefore the sensitivity and cut-off frequency. The objective in this research is to overcome the disadvantages of the prior works by designing a novel MEMS capacitive microphone that utilizes a perforated diaphragm thus achieving small size and improved microphone sensitivity by decreasing the mechanical stiffness of the diaphragm. 2. Microphone design Capacitive microphones generally consist of a diaphragm that is caused to vibrate by impinging waves of acoustic pressure a back plate and air gap. In its simplest form a diaphragm is stretched over a conductive back plate and supported by post so that there is a gap between the membrane and the back plate. Figure 1 shows the basic structure of the condenser microphone. A diaphragm is stretched by a tensile force T is put in front of a fixed conducting back plate by means of a surrounding border which assures a separation distance d to create a capacitance with respect to the back plate and biased with a DC voltage. An acoustic wave striking the diaphragm causes its flexural vibration and changes the average distance from the back plate. The change of distance will produce a change in capacitance and charge giving rise to a time varying voltage V on the electrodes. This structure works as a condenser whose static capacitance is Pappalardo et al. 2002 A C So a 1 d where o is the dielectric constant of the air and A is the surface area of the metallized membrane. Fig. 1. Basic structure of the condenser microphone When a DC voltage VDC is applied between the two electrodes an electric charge QDV C0VDC appears on the surface of the membrane where C _ s0A d XDC 2 accounting for the gap height variation due to the bias voltage and XDC is the static average displacement due to the DC electrostatic force. In reception an acoustic wave striking the Design and Fabrication of a Novel MEMS .

TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.