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VinnyCee

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I need to make an impedance matching circuit using microstrip lines.

Zin --> MATCHING CIRCUIT --> ZL

The input impedance (Zin) is 50Ω. The impedance at the load is 50 - j 500Ω. Design frequency of 900MHz.

The board I am required to use is the Taconic RF-35. It has a thickness of d = 1.524mm, dielectric constant ξr = 3.5 and loss tangent σ = 0.002.

The magnitude of S11 at the design frequency must be less than -10dB. The size of the circuit is of particular importance. How can I make the microstrip impedance matching circuit smaller?

To start, I got the normalized load impedance of 1 - j 10Ω and plotted that on a Smith chart.

Now I have to use the Smith chart to find what inductance and/or capacitance I should use to match the two ports. After I get those numbers, I could used lumped elements to do the matching, but I must use microstrip lines instead.

After finding the required matching numbers, I will use an open stub to do the matching, I think. My questions are:

1) How do I improve the bandwidth (resonant frequency of 900MHz)? Maybe 875MHz - 925MHz?

2) How do I reduce the physical size of the impedance matching circuit? <---- MOST IMPORTANT

3) How do I increase the voltage sensitivity of the impedance matching circuit?

Zin --> MATCHING CIRCUIT --> ZL

The input impedance (Zin) is 50Ω. The impedance at the load is 50 - j 500Ω. Design frequency of 900MHz.

The board I am required to use is the Taconic RF-35. It has a thickness of d = 1.524mm, dielectric constant ξr = 3.5 and loss tangent σ = 0.002.

The magnitude of S11 at the design frequency must be less than -10dB. The size of the circuit is of particular importance. How can I make the microstrip impedance matching circuit smaller?

To start, I got the normalized load impedance of 1 - j 10Ω and plotted that on a Smith chart.

Now I have to use the Smith chart to find what inductance and/or capacitance I should use to match the two ports. After I get those numbers, I could used lumped elements to do the matching, but I must use microstrip lines instead.

After finding the required matching numbers, I will use an open stub to do the matching, I think. My questions are:

1) How do I improve the bandwidth (resonant frequency of 900MHz)? Maybe 875MHz - 925MHz?

2) How do I reduce the physical size of the impedance matching circuit? <---- MOST IMPORTANT

3) How do I increase the voltage sensitivity of the impedance matching circuit?

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