54 / 84
with no filters. This represents an
improvement over traditional filters
in the range of 5.5 to 12 dB.
Conclusion
Maximizing linearity and dynamic
range has always been a goal in
RF transceiver design. The IP3
of the mixer itself is one obvious
factor limiting system performance,
but even the best mixers produce
of 1 MHz, and IF output of 150
MHz. The test setup is illustrated in
Figure 2 and the test conditions are
summarized in Table 3.
Low and high third order
intermodulation frequencies were
measured at IF output for all cases
and compared. Summary results
are presented in Table 4. Again, for
brevity, only measurements for RF
input of 800 MHz are shown here,
but RF input of 2200 MHz produced
similar results.
Again we see that reflectionless
filters achieve a reduction of
IM 3 levels when compared to
conventional filters in the same
circuit. Third order intermodulation
performance with reflectionless
filters on the mixer RF input and IF
output is nearly equal to or slightly
better than that of the mixer alone
Table 2: Summary Results of Two-Tone Intermodulation Test in Up-converter Configuration
Mixer
Test
Freq.
MHz
Filter
Type
IF FIL-
TERS
IF
FILTER
@F1dB
MHz
RF
FILTERS
RF
FILTER
@F1dB
MHz
IM 3
(dBc)
799 MHz
IM 3
(dBc)802
MHz
∆IM 3
(dB)802
MHz
∆IM 3
(dB) 799
MHz
ADE-
10H+ 149&150 None
-
N/A
-
N/A 72.2
70.4
0.3
0.6
ADE-
10H+ 149&150 L-C SLP-
150+ 155 SLP-
1000
950
53.6
52.9 (17.2)
(18.0)
ADE-
10H+ 149&150 L-C SLP-
150+ 155 SLP-
1200+ 1050 64.7
63.9
(6.2)
(6.9)
ADE-
10H+ 149&150 LTCC VLF-
160+ 160 VLF-
800+ 950
51.0
50.8 (19.3)
(20.6)
ADE-
10H+ 149&150 LTCC VLF-
160+ 160 VLF-
1000+ 1100 49.9
79.9
(9.8)
(21.7)
ADE-
10H+ 149&150 Non-Ref.
XLF-
151+ 150 XLF-
861+ 840
71.6
70.1
Rfrnce Rfrnce
ADE-
10H+ 149&150 Non-Ref.
XLF-
151+ 150 XLF-
122+ 1200 71.8
70.4
SYM-
30DHW+ 149&150 None
-
N/A
-
N/A 58.9
59.0
(3.7)
(3.6)
SYM-
30DHW+ 149&150 L-C SLP-
150+ 155 SLP-
1000
950
51.3
50.9 (11.8)
(11.2)
SYM-
30DHW+ 149&150 L-C SLP-
150+ 155 SLP-
1200+ 1050 57.2
56.4
(6.3)
(5.3)
SYM-
30DHW+ 149&150 LTCC VLF-
160+ 160 VLF-
800+ 950
48.2
48.2 (14.5)
(14.3)
SYM-
30DHW+
149&150 LTCC VLF-
160+
160 VLF-
1000+
1100 48.6
48.6
(14.1)
(13.9)
SYM-
30DHW+
149&150 Non-Ref. XLF-
151+
150 XLF-
861+
840
62.5
62.7
Rfrnce Rfrnce
SYM-
30DHW+
149&150 Non-Ref. XLF-
151+
150 XLF-
122+
1200 62.8
63.0
Test & Measurement
Special Edition
54 l New-Tech Magazine Europe