Microwave Transition Analyzer Research Articles

КОАКСИАЛЬНОЕ КОНТАКТНОЕ УСТРОЙСТВО И СПОСОБ ЕГО КАЛИБРОВКИ

A coaxial contact device for connection to the microwave transition analyzer is proposed as coaxial measures for calibrating the analyzer, and the investigated strip line junctions for measuring their S-parameters. In addition, a method for calibrating this device with one or two calculated coaxial-to-stripline calibrators, providing the transfer of the results of calibration of the analyzer by coaxial measures to the measurement of S-parameters of the strip line junctions is presented.

Thru-less calibration algorithm and measurement system for on-wafer large-signal characterisation of microwave devices

A reflection-based thru-less de-embedding technique for voltage and current waveforms and absolute power flow measurements suitable for on-wafer large-signal characterisation of microwave transistors is proposed. Based on the novel calibration technique developed, which does not require any special `golden standard` for waveform calibration purposes, a comprehensive and relatively inexpensive power flow, impedance and waveform measurement system, using the microwave transition analyser as a two-channel receiver, is developed. The proposed calibration algorithm is fast, simple and accurate for power de-embedding and waveform measurements. This kind of on-wafer power de-embedding and waveform measurement is helpful in the design of switching-mode power amplifiers. The developed system was tested for both 50Ω and non-50Ω terminated passive and active devices, and the obtained results show very good agreement with those obtained with commercial instruments.

Extraction of nonlinear parameters of dispersive avalanche photodiode using pulsed RF measurement and quasi-DC optical excitation

A measurement system using a pulsed RF signal is presented for extraction of nonlinear parameters of a large-signal model (LSM) of a dispersive avalanche photodiode. Nonlinear model of the avalanche photodiode was considered as two-port network and vector reflection measurement was carried out using a microwave transition analyzer in pulsed RF mode in conjunction with synchronized pulsed optical stimulus on the photodiode. Square-wave optical stimulus of 5-/spl mu/s width (full width at half maximum) and 5-kHz pulse-repetition frequency (quasi-dc) were synchronized with the pulsed RF excitation using a synchronization circuit. High-frequency dispersion effects were taken into consideration for deriving the current through the photodiode and the theoretical background was given for the derivation of optical and bias-dependent parameters. Nonlinear parameters of LSM of the avalanche photodiode were extracted from the small-signal vector reflection measurement at different bias points and optical conditions. Thermal impedance of the device limits the continuous-wave measurement up to 0.1 mW of optical power, whereas when using the current method, it was possible to characterize the device up to 1.3 mW of peak optical power.

Multitone power and intermodulation load-pull characterization of microwave transistors suitable for linear SSPA's design

In this paper, an experimental load-pull characterization of microwave transistors operated under N-tone-excitations (2/spl les/N/spl les/32) is presented. Such characterization is very useful to investigate the linearity of high-power amplifiers via intermodulation distortion analysis. All the measurements were carried out using a newly developed multiline measurement system which uses an arbitrary waveform generator (AWG) to generate the spectrum of any N desired tones and a microwave transition analyzer (MTA) as a vector receiver. The measured intermodulation rejection (IMR) behavior, as the number of tones increases, is compared with previously published theoretical results. Constant output power contours and IMR contours in the /spl Gamma//sub L/(f/sub 0/) plane for different number of tones are presented and discussed. The dependency of the IMR on the biasing conditions and the carriers' phase distribution is also investigated.

Forward volume wave microwave envelope solitons in yttrium iron garnet thin films: Peak profiles and multisoliton signatures (abstract)

Microwave envelope solitons have been observed in yttrium iron garnet (YIG) films for different field configurations and surface pinning conditions. Earlier work on magnetostatic forward volume wave (MSFVW) solitons in YIG films has focused on the break from the low power linear dependence of the output pulse peak power Pout on input pulse power Pin,1 or on the evolution of the shape of the microwave pulse envelope with increasing power.2 In this work, both (1) the nonlinear dependence of Pout on Pin and (2) the shape of the output pulses for MSFVW solitons have been examined over a wide range of power levels and pulse widths. The experiments used 7.2-μm-thick single crystal YIG films with unpinned surface spins. A field of 3744 Oe was applied perpendicular to the plane of a 15×2 mm film sample. Microwave pulses at 5.4–6 GHz, with a width τ of 5–50 ns and peak powers up to 3 W, were launched by a microstrip antenna about 5 mm from one end and picked up by a second, parallel antenna about 5 mm from the other end. Data were processed with a microwave transition analyzer operated in a time domain mode. For a given pulse width, the initial break and nonlinear increase in Pout relative to Pin noted in Ref. 1 is followed by a gradual leveling off in Pout at high power. For a given pulse power above soliton threshold, the Pout versus τ profiles show an initial linear increase which is followed by a decrease and an oscillatory response as multiple solitons are formed. These profiles are directly correlated with the formation of a single soliton pulse which evolves into multiple soliton wave packets with increasing either power or pulse length.

Backward volume wave solitons in a yttrium iron garnet film (invited) (abstract)

Solitons are nonlinear propagating wave pulses that preserve their shape without spreading. Recently, microwave envelope solitons have been observed in thin yttrium iron garnet (YIG) films for magnetostatic surface wave and forward volume wave configurations. In this work, we report the first observation of microwave envelope of magnetostatic backward volume waves (MSBVW) for an in-plane magnetized YIG film with waves propagating parallel to the magnetization direction. Both soliton profiles and the nonlinear peak power response were observed. The experiments were conducted using a microstrip magnetostatic wave delay line structure. A single crystal YIG film of 7.2 μm thickness, 2 mm×15 mm in size, and with unpinned surface spins was magnetized in-plane by a static external field of 1343 Oe along the long 15 mm edge. The 10 GHz ferromagnetic resonance linewidth of the film was 0.6 Oe. Square microwave pulses with pulse widths from 2 to 200 ns and a carrier frequency of 5.78 GHz were launched parallel to the field through a microstrip antenna. The output signal was received by a second microstrip antenna placed 4 mm downstream and analyzed in the time domain with a microwave transition analyzer. Envelope soliton behavior evident from the time resolved waveforms was observed for various input-power/pulse-width combinations. At relatively low power levels, one sees a broad output signal with a peak power increasing linearly with the input power. As the input power is increased above some threshold, a sharp soliton pulse emerges and the peak power increases more rapidly with input power than in the low power regime. The threshold varies with pulse width, as expected for solitons. A further increase of the input power produces multiple soliton profiles and a corresponding drop in the peak power. These results clearly demonstrate the existence of MSBVW solitons in YIG films. Dr. J. D. Adam of Westinghouse is acknowledged for providing the YIG films. This work was supported in part by the National Science Foundation, Grant No. DMR-8921761 and by the U. S. Army Research Office, Grant No. DAAL03-91-G-0327.