CHAPTER 4 - Impedance Matching
152
Figure 4.1-2 Load impedance (50 – j Ω) does not match source impedance (50 Ω)
Figure 4.1-3 Matching network transforms load impedance, as seen by source terminals, into source impedance.
When it comes to impedance matching there are three main combinations of load and source
impedances which we may encounter:
1) Two unequal real terminations
2) One complex, one real termination
3) Two arbitrary complex terminations
Although it is quite easy to just regurgitate established procedures and the respective equations,
throughout this section we will try to explain things from a conceptual point of view, as we have
done throughout this treatment. To this end we will first start with a review of voltages and currents
across parallel and series combinations of resistive and reactive components (RLC networks).
Subsequently we will illustrate the techniques employed to design matching networks for purely
resistive impedances (section 4.3) and then for any arbitrary complex impedances (section 4.4).
ACVS
ID=V1
Mag=1 V
Ang=0 Deg
Offset=0 V
DCVal=0 V
RES
ID=R1
R=1 Ohm
RES
ID=R2
R=1 Ohm
CAP
ID=C1
C=1e-6 uF
V
S
R
S
= 50 Ω
C
L
= -1j Ω
R
L
= 50 Ω
Z
L
=50-j Ω
RES
ID=R2
R=50 Ohm
RES
ID=R1
R=50 Ohm
ACVS
ID=V1
Mag=1 V
Ang=0 Deg
Offset=0 V
DCVal=0 V
IND
ID=L1
L=1 nH
V
S
R
S
= 50 Ω
C
L
= -1j Ω
R
L
= 50 Ω
L
L
= 1j Ω
Z
L
= 50Ω
Conquer Radio Frequency
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