一种叠层带状线电调滤波器的设计

The Design of a Laminated Stripline Electrically Tuned Filter

滤波器在无线通信系统中起选通频带和信道的作用,且能滤除谐波,抑制杂散。随着电子系统集成化的发展,平面耦合滤波器因体积大而不能适应现代无线移动通讯系统小型化、轻型化的要求。该文设计了一款基于低温共烧陶瓷（LTCC）技术的抽头式叠层带状线电调滤波器。该滤波器基于宽边耦合原理,比传统电调滤波器尺寸减小50%以上,由于该滤波器采用叠层结构,能在滤波器的通带两端各产生一个传输零点,使其能得到较高的带外抑制度。该叠层带状线滤波器的中心频率为2.4GHz,调谐范围为2.1~2.7GHz。整个频段内驻波比小于1.25,插损小于1.3dB,尺寸仅为4.8mm×4.5mm×0.6mm,同时满足了小型化和高性能的要求。

Filter plays the role of a selected pass-band and channel in wireless communication system,which is able to filter out harmonic and suppress stray.With the development of the electronic system integration,the planar coupling filter is too large and flat to adapt the requirements of miniaturization,light-weight in the modern wireless mobile communication system.A laminated strip-line adjustable electric filter based on low temperature co-firing ceramic（LTCC）technology was designed.Using the principle of the broad-brimmed coupling,the size of the filter decreases by more than 50%compared with the traditional electric adjustable filter.Due to the laminated structure,the filter could produce a transmission zero at each side of band-pass filter to get higher degree of restraint outside the band.The center frequency of the laminated strip-line filter was 2.4GHz with tuning range of 2.1~2.7GHz.The voltage standing wave ratio in the frequency band was less than 1.25,the insertion loss was less than 1.3dB,the size was only 4.8mm×4.5mm×0.6mm,which could fulfill the requirement of the miniaturization and high performance at the same time.