70-700 GHz, high dynamic range vector spectroscopy

VNA and VNA/VDI systems at UCSB

Facility Director:   Professor Mark Sherwin (sherwin-at-itst.ucsb.edu)

Facility Manager:   Nikolay Agladze (nick-at-itst.ucsb.edu)

Location:   Broida Hall 1217 (UCSB Campus Map)

Recharge Rates: Equipment: (Subject to changes.)  User Login






Recharge Rates: Equipment: (Subject to changes.)

Service Description*   Billing Unit Rate
UCSB Users    Day $49.14/Hour
Non UCSB Users   Day $80.00/Hour
UCSB Users Training/Setup   Hour $123.40/Hour
Non UCSB Users Training/Setup    Hour $192.00/Hour


(A source and detection of tunable, coherent, large dynamic range and wide IF bandwidths microwave radiation) The Vector Network Analyzer (VNA) and the combination of VNA and Virginia Diode (VNA/VDI) systems at the UCSB Center for Terahertz Science and Technology consist of two microwave bands: the VNA covering the range of 10 MHz to 40 GHz and the VNA/VDI system covering the range of 70 GHz to 700 GHz (0.43 to 4.3 mm or 2.3 to 23.3 cm-1). The power can be varied over a wide dynamic range up to 140 dB and the output power up to 15 dBm. The system has a wide IF bandwidths from 1 Hz to 18 MHz. Its large IF bandwidths and fast synthesizers combine to yield short measurement times and thus high throughput in manual adjustments and automated production sequences. The measurement time per test point is less than 3.5 μs in the CW mode; a frequency sweep over 200 test points takes less than 5 ms. The system provides various tools to optimize the display and analyze the measurement data. The source launches a signal at a single frequency to detect the reflected or transmitted signals from the mater. By changing the display format we can obtain the information about the phase shift, the impedance of the reflected or transmitted waves of your material. The source is then stepped to the next frequency and the measurement is repeated to display the reflection or transmission as well as phase shift, impedance measurement response as a function of frequency. The system can run in a continuous range of the sweep variable (frequency/power/time) containing the sweep points where the analyzer takes measurements. In the Frequency mode the frequency sweep range can be in a larger range (or whole frequency band) with a fixed power; in the Power mode the wide dynamics range up to 140 dB can be used; in the Continuous Wave mode the fixed stimulus frequency and power are used; in a Segmented Frequency mode the sweep range can be composed of several parameter ranges or single points. Measurements on pulsed RF signals are required in many areas of RF and microwave technology. Pulsed signals are used in mobile phone applications and radar systems, and amplifiers are typically designed for pulsed rather than continuous wave (CW) conditions. The analyzer performs pulsed measurements in analogy to a time sweep (i.e. at constant receiver frequency), but with a much higher sampling rate of 12.5/ns. The raw I/Q amplitudes are written into a ring buffer and processed at the end of each sweep. The buffer size allows for a maximum recording time (sweep time) of 3 ms. Due to the high sampling rate and the large IF bandwidths available, it is possible to obtain profiles for pulse widths from approx. 200 ns to the maximum recording time. Of course it is also possible to measure a sequence of pulses up to the maximum recording time. The VNA and VNA/VDI offer a perfect balance between measurement speed, dynamic range, flexibility, and precision, making them ideal for present and future measurement tasks.