| 摘要 |
PURPOSE:To obtain a band stop filter with simple constitution set for a high order optional band stop frequency by providing at least a resonator whose line characteristic impedance is different from an open part and a short-circuit part. CONSTITUTION:Tip open lines 21, 22 consist of lines 24, 25 and 26, 27 whose characteristic impedance is different from each other. Through the constitution above, the high-order block band is deviated from an odd number multiple by using a resonator (SIR) whose characteristic impedance is changed stepwise for the tip open lines 21, 22. The resonance condition of the SIR is simplified as tan<2>theta=K,Z1/Z2=K, where Z1 is the characteristic impedance of the line 24 or 26 of the open end, theta1 is the electric length, Z2 is the characteristic impedance of the line 25 or 27 of the short circuit end, theta2 is the electric length and theta1, theta2 are selected as theta1=theta2=theta to attain simple design. The resonance condition of the SIR depends on the impedance ratio K. |
