This month’s featured RF and microwave products range from amplifiers and signal sources to a very flexible active load pull system. With the existing large choice of amplifiers, there must be something special about the two included here, and there is. In one case, the frequency range is provided as two bands, which suits the application while also reducing harmonics. In the other case, GaN devices were used to provide both high power levels as well as low distortion.
For the greatest flexibility, signal sources are synthesized, which requires innovative design techniques to minimize noise. A family of synthesizers is based on the low noise of a basic 20-GHz unit with additional multipliers providing three distinct mmWave bands. In another product, a multiloop architecture contributes to very low harmonic and spurious levels. Finally, several models of an active load pull system handle wideband modulated signals from 1 GHz to 40 GHz in either a single-ended or differential configuration.
Real-time spectrum analyzer and RF recorder
The manufacturer’s open-source spectrum analyzer software provides 2D or 3D views as well as a color-graded persistence display. You can select the I/Q data recording rate that best suits your application from 312.5 kS/s to 40 MS/s: USB 3.0 supports up to 140-MB/s sustained throughput to your PC. And, because all the computations are performed in a PC, the manufacturer recommends a desktop model with an Intel quad-core I7-2600 or better or a laptop with an I7-3612QM or better. Signal Hound
Several models of the MT2000 mixed-signal active load pull system cover the 1.0-MHz to 40-GHz carrier frequency range and provide either two or four active tuning loops as standard with five- and six-loop add-ons optionally available. As described in the manufacturer’s technical data 4T-095 document, “This mixed-signal load pull system is designed to handle realistic wideband complex modulated signals with a high dynamic range and provide user-defined reflection coefficients vs. frequency at the DUT reference planes.”
Because the active loops are reconfigurable, you can use the hardware to support source pull at f0 and load pull at f0, 2f0, and 3f0, or you can configure the same hardware for differential source and load pull at f0. In addition, use of a proprietary algorithm minimizes the amplifier requirements. The power output must be somewhat larger than the power generated by the DUT, but linearity is not critical. Maury Microwave
The two-port PLANAR 804/1 VNA determines DUT S-parameters over the 100-kHz to 8-GHz frequency range, accumulating from two to 500,001 measurement points within a chosen scan segment. Transmission measurement accuracy varies from 0.1 dB/1 degree at levels from -50 dB to +5 dB to a maximum of 1.5 dB/10 degree from -70 dB to -50 dB for frequencies between 100 kHz and 300 kHz. From 300 kHz to 8 GHz, accuracy is better than 0.2 dB/2 degree for levels >-70 dB.
Time-domain operation and gating, fixture simulation, and a frequency-offset mode are among the VNA’s features. Embedding and de-embedding, power scanning and compression point recognition, and limit testing are built-in functions that simplify testing and improve accuracy. Up to 16 channel windows can be displayed with up to 16 data traces in each, allowing comparison of previously saved traces with current values. Smith chart and polar diagrams are available as are log or linear magnitude, phase, expanded phase, group delay, standing wave ratio, real part, and imaginary part plots. Copper Mountain Technologies
Models FSL-2740 (27 GHz to 40 GHz), FSL-5067 (50 GHz to 67 GHz), and FSL-7682 (76 GHz to 82 GHz) are based on the manufacturer’s 650-MHz to 20-GHz QuickSyn Lite synthesizer coupled to a suitable frequency multiplier. The original QuickSyn synthesizers were developed by Phase Matrix (now NI Microwave Components) in 2010. NI launched the Lite version in 2013, retaining the benefits of the phase-refining technology that include 100-µs switching speed, lower than -100-dBc/Hz typical phase noise, 1-Hz resolution, and a maximum 15-W power input, all in a compact 4 x 4 x 1.8-inch format.
As described on the company’s website, “The new modules are powered and controlled by the QuickSyn Lite base unit, making integration and control simple for the user. Like all QuickSyn synthesizers, these new mmW sources include serial SPI and USB control interfaces and are immediately deployable by connecting them to a PC and a DC power source. A soft front panel enables the user to access frequency control and frequency sweep plus 32k-point list mode settings. Additionally, embedded firmware allows these modules to be used as part of integrated auto test solutions. National Instruments
With a nonreflective color display, backlit keypad, and long battery life, the 5.5-lb Spectrum Rider handheld spectrum analyzer is well suited for field work. Ruggedized in line with MIL-PRF-28800F class 2, the instrument has no vents or fans and features IP51-type dust and drip protection together with removable interface and connector caps. Nevertheless, RF performance has not been sacrificed as is evident from typical values of -163-dBm DANL, -105-dBc phase noise (1 Hz) at 100-kHz offset (10 MHz to 3 GHz carrier), and 0.5-dB amplitude uncertainty.
The frequency range of the basic instrument is 5 kHz to 2 GHz, but this can be extended to 3 GHz or 4 GHz and enabled via software keycode. Available options are related to improved power measurement capabilities: FPH-K9 allows use of the manufacturer’s NRP-Zxx power sensors with a range of -67 dBm to +45 dBm and covering frequencies up to 110 GHz, FPH-K19 supports power measurements without a separate power sensor, and FPH-K29 provides pulse and peak power measurements with the manufacturer’s NRP-Z8x wideband power sensors. Rohde & Schwarz
For those readers with too much of a good thing, programmable attenuation may be the answer. The Model RCDAT-6000-110 attenuator provides from zero to 110-dB signal reduction in 0.25-dB steps. Importantly, as the datasheet states, “Its unique design maintains linear attenuation change per dB, even at the highest attenuation settings.” Numerically, this is indicated by the typical +53-dBm IP3 value.
Accuracy varies with frequency, being the most consistent for the 2-GHz to 4-GHz band: typically ±0.15 dB to ±0.50 dB. At lower and higher frequencies, typical accuracy at the highest attenuation settings can be as low as ±0.8 dB, although for attenuation less than 40 dB, it is ±0.5 dB or better regardless of frequency. Typical VSWR ranges from 1.05 to 1.3.
Control is via either Ethernet—HTTP or Telnet protocol—or USB, which can power the device. Functionality includes programmable attenuation sweep and hop sequences, a timed sequence of settings that can run without any additional external control. The RCDAT-6000-110 comes with user-friendly GUI software, API objects for Windows environments, and instructions for use with 32-bit and 64-bit Windows and Linux OS. Mini-Circuits
Providing up to 2,000 W in a rack-mountable 8-U package, the Model 2180-BBS4A5KXV broadband amplifier is based on GaN devices that support frequency response from 1,000 MHz to 2,500 MHz, high gain, and low distortion. According to the datasheet, the class-AB design uses “… advanced broadband RF matching networks and combining techniques” to achieve long-term reliability and high efficiency. A built-in monitoring and protection system features graceful degradation at temperatures >40ºC and power reduction to a safe level if VSWR exceeds 2:1.
At the maximum 1-dB compression point, 1,500 W is delivered with a 64-dB gain and a 15-dB gain adjustment range. Both the second and third harmonic levels are guaranteed to be less than -15 dBc at 2,000-W output, and the guaranteed spurious signal level is -60 dBc. Remote management and diagnostics are via an embedded web server. Built-in nonvolatile memory records events and stores factory setup recovery files. Optionally extended memory may be used to store control parameters and log events. EMPOWER RF Systems
One to four phase-coherent channels as well as very low harmonic and spurious levels distinguish the 10-MHz to 6-GHz HSX9000 Series synthesizers. A multiloop architecture ensures both instantaneous and long-term stability, and thermal monitoring allows you to track relative channel temperatures—according to the data sheet, the only remaining contribution to drift.
Each channel of the 1-U high synthesizer can be independently tuned in 0.001-Hz steps. Typical phase offset resolution is 0.1 degree with calibrated output power ranging from -110 dBm to +18 dBm. The maximum SSB phase noise is <-122 dBc/Hz at 10-kHz offset from 3.0 GHz to 6.0 GHz. Lower frequencies are developed by dividing, which improves phase noise by at least 6 dB. For example, for outputs between 375 MHz and 750 MHz, the fundamental range has been divided by two three times—a factor of eight—and the guaranteed phase noise is -142 dBc/Hz—a 20-dB improvement.
With a virtual front panel, the synthesizer operates under the HID protocol and requires no driver installation. It can be controlled via MATLAB, LabVIEW, C++ code, and VB code, to name a few methods. Holzworth Instrumentation