Digital Signal Processing Reference
In-Depth Information
Table 7.6
Measured 2-tone output power and PAE
2 Tone
200 MHz
300 MHz
IMD3
value
Conv.
Tun.
Conv.
Tun.
P
out
(dBm)
3
.
1
7
.
6
6
.
6
5
.
1
−
35 dBc
PA E ( % )
2
.
8
7
.
9
6
.
5
4
.
6
P
out
(dBm)
5
.
9
10
.
5
7
.
8
10
.
1
−
30 dBc
PA E ( % )
4
.
9
15
8
.
5
13
.
9
P
out
(dBm)
16
12
.
5
8
.
7
11
.
9
−
25 dBc
PA E ( % )
2 2
.
1
21
.
9
10
.
2
20
.
1
Fig. 7.25
Photograph of the PCB used in the hybrid implementation
PAs, shown in Fig.
7.24
, reveals that at 300 MHz, there is almost no difference
between their efficiencies.
A photograph of the printed-circuit board (PCB) for this hybrid implementation
isshowninFig.
7.25
. Due to the lower frequencies at which the circuit was tested,
an FR-4 substrate (thickness of 0.5 µm, copper cladding of 17 µm, and
r
of 4.6)
was chosen.
7.6 Analysis and Discussion of the Results
The experimental results obtained with the prototype of the frequency-tunable RF
power amplifier presented in Sect.
7.4
showed that the expected frequency-tunable
behavior did not take place. Looking back at the design, we can say that there were
two main problems that we overlooked and which are intimately related to each
other.
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