vistadude
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I'm trying to implement the low-pass filter from Pozar's Microwave Engineering (2nd ed, p. 466-468) in Microwave Office using the Taconic TLY-5 substrate
(Model TLY_5_200 from the AWR Web site libraries).
Doing that I have encountered a number of questions, which I cannot figure out from the Getting Started and User Guides. (Are there NO books on MWO? I'm
located outside of any areas where MWO courses are offered)
1) Er=2.2 is a reasonably low value for microstrip (correct?). (higher impedance or higher Er equals lower line width to implement) The T/W and W/H ratio's
of the 217.5Ω lines using my chosen substrate is still outside of recommended values, as well as outside of the required values to use MSTEP$.
Is my computed values incorrect, or can the filter not be realized on my chosen substrate?
2) Is schematic 1 an acceptable first approximation of the stub filter? (apart from the ripple, the simulated graph closely matches Pozar's response in
figure 8.37, p. 468)
3) Is schematic 2 (using MTEE$ and MSTEP$) the correct way to model the filter more accurately? (assuming the T/W and W/H issues have been addressed)
PS: The line length was computed as λ/8=(2.9979*0.675)/(40*8) where 2.9979*0.675 accounts for the wave speed in the substrate, 40 for the frequency and 8 for
one eighth wavelength.
(Model TLY_5_200 from the AWR Web site libraries).
Doing that I have encountered a number of questions, which I cannot figure out from the Getting Started and User Guides. (Are there NO books on MWO? I'm
located outside of any areas where MWO courses are offered)
1) Er=2.2 is a reasonably low value for microstrip (correct?). (higher impedance or higher Er equals lower line width to implement) The T/W and W/H ratio's
of the 217.5Ω lines using my chosen substrate is still outside of recommended values, as well as outside of the required values to use MSTEP$.
Is my computed values incorrect, or can the filter not be realized on my chosen substrate?
2) Is schematic 1 an acceptable first approximation of the stub filter? (apart from the ripple, the simulated graph closely matches Pozar's response in
figure 8.37, p. 468)
3) Is schematic 2 (using MTEE$ and MSTEP$) the correct way to model the filter more accurately? (assuming the T/W and W/H issues have been addressed)
PS: The line length was computed as λ/8=(2.9979*0.675)/(40*8) where 2.9979*0.675 accounts for the wave speed in the substrate, 40 for the frequency and 8 for
one eighth wavelength.