New-Tech Europe Magazine | April 2017

Test & Measurement Special Edition

with no filters, reflective filters (lumped element and LTCC), and reflectionless filters at the IF input and RF output ports. Low and high third order intermodulation frequencies were measured at the RF output for all cases and compared. Summary results are presented in Table 2. For brevity sake, results are shown here only for RF output of 800 MHz. Results for RF output of 2200 MHz are comparable and are available by request from Mini- Circuits. Notice that in all cases where reflective filters were used, the filters contribute to a significant increase in thirdorder intermodulation product (IM 3) relative to the IM3 of the mixer when no filters are used. When reflectionless filters are used, however, measured IM 3 is nearly equal to or less than that of the mixer alone. These results therefore demonstrate that using reflectionless filters in the up-conversion circuit achieves an improvement in third order intermodulation performance ranging from about 5 dB to 18 dB relative to performance when conventional filters are used in the same circuit. Down-Conversion Test Setup Two-tone intermodulation tests were performed in downconverter configuration as shown in Figure 2. As in the up-conversion setup, different mixer-filter combinations were tested to compare reflectionless filters with various conventional filters. Mixers were also tested with no filters for reference. Third order intermodulation measurements were made for RF inputs of 800MHz and 2200 MHz with two-tone spacing

Figure 1: Up-conversion test setup

Table 1: Summary of Test Conditions for Two-Tone Intermodulation Test in Up-converter Configuration

• Case 1: NO FILTERS • Case 2: REFLECTIVE FILTERS (VARIOUS) on RF and IF PORTS • Case 3: REFLECTIONLESS FILTERS on RF and IF PORTS

FILTER PO- SITIONS

IF INPUT 150 MHz TONES TWO TONES SPACING: 1 MHz (149 MHz AND 150 MHz)

MIXERS TESTED

•ADE-10H+ •SYM-30DHW+

LUMPED ELEMENT (Sharp Filters)

SLP-1000

IF SLP-1200+ SLP-2400+ SLP-2950+ LTCC FILTERS (Shallow Slope) VLF-1000+ VLF-2250+ VLF-2500+ REFLECTIONLESS FILTERS VLF-800+ IF

RF

SLP-150+

FILTERS TESTED

RF

VLF-160+

XLF-861+ XLF-122+ XLF-252+

RF

IF

XLF-151+

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