Lab05b-Microstrip quarter-wave transformer

Substrate: ¥å_r = 2.5, Tan¥ä = 0.002, H = 0.787mm, Tmet = 0.035mm

Use an online microstrip line calculator: http://www.rfdh.com/rfdb/msline.htm

f = 2.45 GHz

(quarter-wave transformer design formula)

1. Design the following lines.

a) Line 1: Z₀₁ = 50 ¥Ø, line length = ¥ë₁/4 (a quarter-wave line on a 50-ohm line)

b) Line 2: Z₀₂ = (50*100)^1/2 = 71 ¥Ø, line length = ¥ë₂/4 (a quarter-wave line on a 71-ohm line)

c) Line 3: Z₀₃ = 100 ¥Ø, line length = ¥ë₃/4 (a quarter-wave line on a 100-ohm line)

2. Make a structure of lines 1, 2, and 3 connected in sequence.

3. Simulate S11, S12, S21, S22.

4. Analyze the results.

a) Record |S11| minimum value and corresponding frequency.

(Note: In theory, |S11| = -¡Ä dB at 2.45GH.)

b) Record |S22| minimum value and corresponding frequency.

(Note: In theory, |S22| = -¡Ä dB at 2.45GH.)

c) Is the reciprocity condition |S12| = |S21| satisfied?

d) Record the phase of S21 at 2.45GHz.

(Note: In theory, the phase of S21 will be -270 degrees.)