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Microwave measuring devices

Product description: A product line featuring standardized microwave test benches designed for measuring the performance of radio-electronic components and microwave materials when tested in the L, S, C, X, Ku, and Ka frequency ranges.

    Functional configuration of a microwave test bench:
  • A generator unit that generates a probing signal in the desired frequency range
  • A microwave measurement chamber that contains the component (material) being tested
  • A processing unit whose outputs can be visualized on a personal computer

Operating principle: For each frequency range, there is a dedicated high-Q resonant measurement chamber developed to accommodate the microwave path component to be tested and, after the latter has been installed, to facilitate the measurements of the reflectance and transmittance characteristics thereof with an error of 5 % or less (if necessary, the error can be reduced by increasing the chamber’s own Q factor). Based on these data (as well as those obtained when calibrating the test bench using reference components), the processing unit can visualize the following microwave parameters in the selected frequency range: the values of complex impedance, insertion losses, and nonlinear distortion level (for microwave path components) or the values of dielectric permittivity and dielectric loss tangent (for microwave materials). When using a pulsed probing signal, it is possible to visualize the time (down to ns) of switching between the different states of the microwave path component. The proposed microwave test benches can be used for rapid output monitoring during the development and manufacture of electronic components (microwave varactor diodes and voltage-variable capacitors, semiconductor-based and microelectromechanical microwave key pads, microwave transistors and amplifiers) and microwave materials (solid dielectrics).

The devices make it possible to determine the microwave losses occurring in (i. e. evaluate the Q-factor of) semiconductor- and ferroelectric-based varactor diodes at various frequencies of the microwave range (1 GHz, 2 GHz, etc.) for various control voltages. The Q-factor measurement error does not exceed 5 % and practically does not depend on the frequency range. The high measurement accuracy is obtained by using high-Q (Q00 ≥ 2000) measuring resonators and providing a high degree of isolation (≥60 dB) between the resonator and the capacitor control circuits.

The devices make it possible to measure the capacitance of capacitors used in microwave circuits with an error not exceeding 0.1 %. The respective capacitance measurement range is between 0.1 pF and 10 pF.

Characteristic Value
Operating frequency (pilot) f = (1–3) GHz
Time scale for control pulses tp = 1 ns – minutes; Dc
Amplitudes of control pulses Up = (0–300) V; Up = (0–5) kV
Rated capacitance values to be measured C = (0.5–20) pF
Measurement error ΔCerror < 0.1 %

The devices enable high-accuracy (<1 fF) registration of any changes in capacitance distinguishable in the subnanosecond time range, which makes it possible to determine the response speeds of varactor diodes (both ferroelectric- and semiconductor-based). The devices can also determine the level of residual polarization observed in linear ceramic capacitors when they are exposed to pulsed voltages of up to 5 kV.

There is currently no comprehensive system (which would include a transmittance measurement device, a switching time measurement device, a control voltage supply device, and decoupling circuits) designed to analyze MEM components. A versatile device has been developed that makes it possible to measure the microwave S-parameters and the SPxT ON/OFF times for MEM components using standard metrology tools.

Results of testing of SP4T switches of MEM components at a frequency of 2.8 GHz

Insertion loss (|S21|, |S31|, |S41|, | S51|) in the ON state, dB <0.3
Isolation characteristic (|S21|, |S31|, |S41|, |S51|) in the OFF state, dB >35
Matching characteristic (S11, S22, S33, S44, S55) in the ON state, as evaluated on a port-by-port basis, dB <-30
Channel resistance in the ON mode under direct current, Ohm <2.5
Switch-on voltage, V ±100
Switch-off voltage, V 0
Switch-on time, μs 2–10
Switch-off time, μs <1
Switching power, nJ <1
Average power consumption at a control frequency of 1 kHz <1