Design of Even-Order Symmetric Bandpass Filter With Chebyshev Response

Abstract

Abstract-This paper proposes a method to design an even-order symmetric bandpass filter with Chebyshev response. The alternative J inverters and λ/4 short-ended resonators are used in the filter design. It is well known that a conventional even-order Chebyshev bandpass filter prototype can be designed by using Jinverters. However, to achieve the Chebyshev response, a problem is that the output admittance Y L is unequal to the input admittance Y 0 since normalized g n+1 is not equal to the g 0 . Thus, for the symmetrical structure, an additional impedance transform can be installed at the output port to solve this problem, thus the network of even-order symmetric bandpass filter with a Chebyshev response should be modified with new J-inverters. In this work, all J-inverters of the symmetric bandpass filter with Chebyshev response are extracted and described as curves to determine the circuit dimensions of the proposed structure. Two even-order Chebyshev bandpass filters with the second-and fourth-order are designed with the proposed method as its application examples. Finally, the fourthorder filter is fabricated and measured at center frequency of 2.5 GHz with the fractional bandwidth 25%. The measured result is in good agreement with the simulated one.

Design of a Wide-Band Microstrip Filtering Antenna with Modified Shaped Slots and SIR Structure

“…According to the above, for the second-order (N = 2) Chebyshev low pass filter prototype with a passband ripple of 0.5 dB, the element values are g o = 1, g 1 = 1.4029, g 2 = 0.7071 and g 3 = 1.9841. Generally, for the equivalent circuit of the bandpass filter shown in Figure 3b, the theoretical values of the J-inverters can be readily obtained [32] as follows:…”

Design and optimization of microstrip filtering antenna with modified shaped slots and SIR filter to improve the impedance bandwidth

“…As mentioned earlier the second-order (N = 2) Chebyshev low pass filter prototype with passband ripple of 0.5 dB, the element values are 𝑔 𝑜 = 1, 𝑔 1 = 1.4029, 𝑔 2 = 0.7071, 𝑔 3 = 1.9841. Generally, for the equivalent circuit of the bandpass filter shown in Figure 3 (b) the theoretical values of the J-inverters can be readily obtained [32] as follows:…”