Tunable Bandpass Filter

Specifications Tuning range:1.5 GHz to 2.5 GHz Low insertion loss 50  terminations Stable magnitude response over the full tuning range Stable phase response over the full tuning range Consistent tuning characteristics

Design Status After evaluating previous work we have changed the design –The new design is based upon work done by Dr.Boris Kapilevich and published in Applied Microwave & Wireless Extensive simulation has established the following: –We will use a twin varactors with a tuning range of 0.2 to 2.0 pF –The design is shown in Figure 1-1 –The magnitude and phase response of the filter’s transmission coefficient S(2,1) resulting from this arrangement are shown in Figure 1-2 We have found through Sprague Goodman a varactor diode with low parasitic and a high Q value –We are currently waiting for them to provide the simulation model, data, and the physical device to test and implement in our design

Figure 1-1

Figure 1-2

Comparison to Initial Schedule We are roughly 2 or 3 weeks behind schedule for this subsystem We anticipate receipt of data to allow fine tuning simulations before the end of the week We need the varactors to move on to the physical implementation of this subsystem –We anticipate receipt of this within 2 weeks –We will be able to develop the template for the filter’s mask upon completion of the fine tune simulations

New Schedule for this Subsystem Week 1 –Sifted through Dr. Kapilevich’s work for design procedures and equations Week 2 –Lack of design guidelines lead to systematic simulation designing Week 3 –Determined design and tuning capacitance range to fit our needs Week 4 –Found varactor that best meets design needs –Contacted sales rep. for further data, simulation models, and ordering information Week 5 –Placing order today for varactors –Implementing simulation models/data into design for fine tuning

New Subsystem Schedule (continued) Week 6 –Continuing fine tuning simulations –Sending filter template off to the Caterpillar Image lab for development of a mask Week 7 –Verify receipt of varactors –Test varactors –Initiate subsystem construction Weeks 8 & 9 –Continue subsystem construction –Test subsystem –Test the total system’s interconnected functionality Weeks –As per complete system schedule (shown later)