小型化交指型LTCC带通滤波器设计

The Design of a Miniaturized Interdigital LTCC Bandpass Filter

摘要: 本文提出了一种基于LTCC技术的小型化交指型带通滤波器的设计方法，通过在交指线末端加载对地电容，压缩了谐振器尺寸，将对地电容布置在分立的空间中，避免了电容间的耦合干扰，引入非相邻谐振器间交叉耦合，在通带两端各产生一个零点，提高了边带抑制。设计了一款中心频率2.3 GHz，带宽200 M交指型带通滤波器，插损小于2.5 dB，通带波动优于0.5 dB，利用三维仿真软件HFSS建模及优化，并利用LTCC工艺加工制造，尺寸仅为3 mm × 2 mm × 1.5 mm，经测试，实际测试曲线与仿真曲线符合较好，验证了设计的有效性。

Abstract: A method of designing miniaturized interdigital bandpass filter based on LTCC technology was proposed, through loading ground capacitance at the end of interdigital transmission line, com-pressed the volume of resonator, to arrange the ground capacitance in discrete space, avoided the coupling interference between themselves, then cross-coupling was introduced between nonad-jacent resonator, generated two transmission zeros on both sides of the passband and improved the sideband suppression. A interdigital bandpass filter with center frequency 2.3 GHz and bandwidth 200 M was designed, the insertion loss was less than 2.5 dB, passband fluctuation was better than 0.5 dB, HFSS was used to construct the 3D model and optimize the simulated results, then fa-bricated the filter with LTCC technology, the size was only 3 mm × 2 mm × 1.5 mm, the measured curves confirmed well with the simulated curves, verified the validity of the design.