</table>
== Realizing a Microstrip Version Designing Two Sets of the Coupled Line Bandpass FilterMicrostrip Lines == [[File:RF99.png|thumb|580px|The RF.Spice schematic of the coupled microstrip bandpass filter.]] In the last part of this tutorial lesson, you will design and test a microstrip realization of the coupled line bandpass filter you simulated in the previous part. For this purpose, you will use a substrate of thickness h = 1.6mm with ε<sub>eff</sub> = 3.4. You will assume a lossless substrate (tand = 0). Remember that in the previous section, TEM line segments with ε<sub>eff</sub> = 1 were assumed and the length of the coupled line segments were set to be a quarter free-space wavelength at 2GHz. For this part, first you need to design coupled microstrip lines with the given even and odd mode impedances. Then, you have to calculate the guide wavelengths of the couple microstrips at 2GHz. You will do these using [[RF.Spice]]'s Device Manager.
Open the "Coupled Microstrips Designer" dialog from In this part of the RF Menu tutorial lesson, you will design and test a microstrip realization of Device Editor. Enter the coupled line bandpass filter you simulated in the previous part. For this purpose, you will use a substrate [[parameters]]: of thickness h = 1.6mm and er with ε<sub>eff</sub> = 3.4. Enter the Z0e and Z0o values for the two types of coupled line segments from You will assume a lossless substrate (tand = 0). Remember that in the previous section and calculate width and spacing of the coupled microstrip lines for each case. Then, open the "Coupled Microstrips Calculator" dialog from the RF Menu of Device Editor. Enter the calculated microstrip width and spacing values to verify your design and also find the corresponding guide wavelengths TEM line segments with &lambdaepsilon;<sub>geff</sub> at 2GHz. The lengths = 1 were assumed and the length of the coupled microstrip line segments are chosen were set to be a quarter of the corresponding guide free-space wavelength at 2GHz. The following table summarizes For this part, first you need to design coupled microstrip lines with the given even and odd mode impedances. Then, you have to calculate the guide wavelengths of the couple microstrips at 2GHz. You will do these using [[parametersRF.Spice]] of the coupled microstrip segments L1, L2, L3 and L4's Device Manager.
Open the '''Coupled Microstrips Designer''' dialog from the Tools Menu of Device Manager. Enter the substrate [[parameters]]: h = 1.6mm and er = 3.4. Enter the Z0e and Z0o values for the two types of coupled line segments from the previous section and calculate width and spacing of the coupled microstrip lines for each case. Then, open the '''Coupled Microstrips Calculator''' dialog from the Tools Menu of Device Manager. Enter the calculated microstrip width and spacing values to verify your design and also find the corresponding guide wavelengths λ<sub>g</sub> at 2GHz. The lengths of the coupled microstrip segments are chosen to be a quarter of the corresponding guide wavelength at 2GHz. The following table summarizes the [[parameters]] of the coupled microstrip segments L1, L2, L3 and L4.
{| class="wikitable"
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== Realizing a Microstrip Version of the Coupled Line Bandpass Filter==
[[File:RF99.png|thumb|580px|The RF.Spice schematic of the coupled microstrip bandpass filter.]]
Build your microstrip circuit using four "Coupled Mirostrips" parts with the [[parameters]] specified in the above table. Connect them in a cascade fashion as shown in the opposite figure. Run a network analysis of this two-port circuit. Set the start and stop frequency of the sweep to 1GHz and 3GHz, respectively, with a linear step of 10MHz. Generate an amplitude-only, Cartesian graph of the S-[[parameters]]. The graphs of s11- and s21 [[parameters]] are shown in the figure below and agree perfectly with the results of the previous section.