【摘要】 在Chebyshev原型滤波器基础上引入衰减极点来获得准椭圆低通滤波器的集总参数电路,并分别采用哑铃型和螺旋型缺陷接地结构实现其串联支路的电感和高外Q值LC并联谐振电路,再采用加宽微带线实现其并联支路电容,从而获得了具有良好的频率选择性及谐波抑止特性且整体结构紧凑的DGS准椭圆低通滤波器.由于该设计方法完全采用解析公式计算,故具有快速有效的优点.最后研制了一个工作频率为2.4GHz的5阶准椭圆低通滤波器,其通带内最大插损小于0.5dB,衰减超过20dB的阻带宽度为13GHz,纵向长度大约为1/4工作波长.更多还原

【Abstract】 The equivalent circuits of a compact Quasi-Elliptic low-pass filter(QELPF) are derived from the Chebyshev prototype circuits by introducing an attenuation pole,which has excellent performance in selectivity and harmonic suppression.The inductances in series branch circuits of QELPF are realized by dumb-bell-shaped defected ground structures(DB-DGSs),the high external quality factor of LC parallel resonance circuits in series branch circuits are realized by spiral-shaped defected ground structures(SP-DGSs),and the shunt capacitances are realized by broadened microstrip lines.Since the design expressions are all analytical,this design process of QELPF is fast and accurate.Finally,a five-pole QELPF for 2.4GHz is developed.The simulated and measured results show that passband insert-loss is less than 0.5dB and the stopband width with 20dB attenuation is over 13GHz.Furthermore,its size in the lengthwise direction is only about 1/4 wavelength.更多还原