What is in this article?:
- Multicarrier Converters Conquer Ku/Ka Bands
- A Tale Of The Numbers
These frequency upconverters and downconverters help reduce the complexity of satcom system infrastructure while also providing improved performance levels at Ku- and Ka-band frequency bands.
A Tale Of The Numbers
Taking a closer look at the frequency downconverters, each is specified for input and output return loss (at 50 Ω) of 18 dB. The downconverters provide two or three IF outputs at +18 dBm or more output levels, with 30-dB gain, flat within ±3 dB. Gain can be adjusted independently for each IF output, in increments of 0.2 dB, over a gain-control range of 30 dB. At constant temperature, the gain is stable within ±0.25 dB/day and within ±2 dB over a 1-GHz bandwidth and temperature range of -40 to +50ºC. The frequency downconverters exhibit worst-case amplitude response of ±0.5 dB per 40 MHz of bandwidth and ±1 dB per 1 GHz of bandwidth. The rugged little downconverters achieve in-band spurious performance of -65 dBc with 80-dB minimum image rejection and worst-case noise figure of 15 dB at the minimum attenuation level.
The phase-noise levels are tightly controlled for all of the compact Ku- and Ka-band frequency downconverters, whether the units provide two or three IF outputs. As an example, model DNB2-W-20.45 is a wideband frequency downconverter with two IF outputs at 1.5 to 2.0 GHz and 1.0 to 2.0 GHz. They represent the translated RF signals from bands of 19.7 to 20.2 GHz and 20.2 to 21.2 GHz (from a single RF input port), via LOs of 18.2 and 19.2 GHz.
Model DNB3-W-29.5-1.5 is a wideband frequency downconverter with three IF output ports, all from 0.95 to 2.45 GHz. They are the downconverted frequencies from RF bands of 27.0 to 28.5 GHz, 28.3 to 29.8 GHz, and 29.5 to 31.0 GHz, again by way of a single RF input port, and translated by means of LOs at 26.05, 27.35, and 28.55 GHz. For both wideband frequency downconverters, the phase noise is low. At Ku-band frequencies (about 12 to 18 GHz), the phase noise is -48 dBc/Hz offset 10 Hz from the carrier, -73 dBc/Hz offset 100 Hz from the carrier, -103 dBc/Hz offset 1 kHz, -112 dBc/Hz offset 10 kHz, and -132 dBc/Hz offset 1 MHz.
At Ka-band frequencies (about 26.5 to 40.0 GHz), the phase noise is -41 dBc/Hz offset 10 Hz from the carrier, -64 dBc/Hz offset 100 Hz, -94 dBc/Hz offset 1 kHz, -102 dBc/Hz offset 10 kHz, and -124 dBc/Hz offset 1 MHz. These frequency downconverters are also specified for phase noise at K-band frequencies (about 18 to 27 GHz), with performance levels of -42 dBc/Hz offset 10 Hz, -67 dBc/Hz offset 100 Hz, -97 dBc/Hz offset 1 kHz, -106 dBc/Hz offset 10 kHz, and -126 dBc/Hz offset 1 MHz from the carrier.
Housed in similarly compact enclosures, the wideband frequency upconverters provide performance levels that are likewise outstanding. They also feature 18-dB input and output return loss, slightly less gain at 27 dB, but similar 30-dB gain-control range, adjustable in 0.2-dB steps. The gain stability is similar to that for the downconverters, with similar image-rejection and spurious performance levels. As with the frequency downconverters, the maximum peak-to-peak group delay per channel is 1 ns, and worst-case noise figure is 15 dB at the minimum attenuation level.
The frequency upconverters also offer excellent phase-noise characteristics. To provide examples, model UPB2-W-13.625 is an upconverter which works with separate IF input ports at 0.95 to 1.45 GHz and 0.95 to 1.70 GHz, which are translated by means of LOs at 11.8 and 12.8 GHz to RF bands of 12.75 to 13.25 GHz and 13.75 to 14.50 GHz, available at a single RF output port. Model UPB3-W-29 is a frequency upconverter with three IF input ports, all operating at 0.95 to 1.75 GHz, translated with the assistance of LOs at 27.05, 27.75, and 28.45 GHz, to three RF output bands at 28.0 to 28.8 GHz, 28.7 to 29.5 GHz, and 29.4 to 30.0 GHz, available at a single RF coaxial output port.
The phase-noise performance is similar to that for the frequency downconverters. At Ku-band frequencies, the phase noise is -48 dBc/Hz offset 10 Hz from the carrier, -73 dBc/Hz offset 100 Hz, -103 dBc/Hz offset 1 kHz, -112 dBc/Hz offset 10 kHz, and -132 dBc/Hz offset 1 MHz from the carrier. At Ka-band frequencies, the phase noise is -42 dBc/Hz offset 10 Hz, -67 dBc/Hz offset 100 Hz, -97 dBc/Hz offset 1 kHz, -106 dBc/Hz offset 10 kHz, and -126 dBc/Hz offset 1 MHz from the carrier.
Such outstanding satcom frequency-converter performance comes from enclosures that measure just 13.0 x 9.90 x 7.25 in. (330.2 x 251.5 x 184.0 mm) and weigh nominally 17 lbs (7.71 kg) or no more than 20 lbs (9.07 kg) with options. The frequency converters use SMA female connectors below 17 GHz, 3.5-mm connectors below 17 to 22 GHz, 2.9-mm connectors above 26.5 GHz, and N female connectors at L-band frequencies. These rugged outdoor units are designed for operating temperatures from -40 to +50°C and altitudes to 10,000 ft. Between their small physical size and ability to pack two or three frequency bands into a single box, they represent a major step toward the simplification of satcom infrastructure.
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MITEQ, Inc., 100 Davids Dr., Hauppauge, NY 11788; (631) 436-7400, FAX: (631) 436-7430.