Abstract: A multi-octave hybrid harmonic load pull tuner comprises a slabline with an adjustable signal coupler (wave-probe) and two multi-carriage slide screw tuners, one in the feedback signal injection loop and one as a pre-matching transformer. The wave-probe controls the static amplitude and phase of the feedback signal and the harmonic tuner in the loop controls the actual amplitude and phase of the re-injected signal at each harmonic frequency separately. De-embedding fast calibration and search routines allow identifying tuner states satisfying instantaneously impedance targets over the entire harmonic spectrum.

Abstract: An active split-signal Fo and 2Fo harmonic impedance load pull tuner uses a single signal source, a wideband harmonic amplitude and phase modulator-frequency doubler. The Fo source signal path is divided between input and output of the DUT; the output portion is processed to generate independently controlled synchronous amplitude and phase controlled Fo and 2Fo signals, which are then amplified and re-injected into the output of the DUT after being pre-matched using a passive harmonic tuner. A harmonic receiver is used to synthesize in situ the required Fo and 2Fo load impedances. Passive 3Fo tuning is also possible independently.

Abstract: A waveguide low profile slide-screw impedance tuner, for high tuning range (GAMMA) and seamless on-wafer integration, uses spring-loaded control of gold-plated alumina (Al2O3) tuning probe, controlling amplitude and phase of the reflection factor using miniature high precision piezo-electric actuators. This ensures the highest possible passive reflection factor GAMMA at THz frequencies. The tuner is integrated on appropriately modified commercially available THz waveguide wafer probes.

Abstract: An active split-signal Fo and 2Fo harmonic impedance load pull tuner uses a single signal source, a wideband harmonic amplitude and phase modulator-frequency doubler. The Fo source signal path is divided between input and output of the DUT; the output portion is processed to generate independently controlled synchronous amplitude and phase controlled Fo and 2Fo signals, which are then amplified and re-injected into the output of the DUT after being pre-matched using a passive harmonic tuner. A harmonic receiver is used to synthesize in situ the required Fo and 2Fo load impedances. Passive 3Fo tuning is also possible independently.

Abstract: A wideband hybrid harmonic high-speed impedance load pull tuner uses the active loop feedback technique combined with transmission type electronic tuner in the active feedback loop and electro-mechanical slide screw harmonic pre-matching tuning. The tuner allows millisecond two or three harmonic tuning with maximum Gamma close to 1 using reduced feedback injection power compared to purely active systems. The system is pre-calibrated and allows fast precision tuning even under nonlinear feedback amplifier power conditions when operated with in-situ wave measurement. Using wideband power dividers, instead of band-limited circulators, to convert the reflection electronic tuner into a transmission amplitude and phase modulator, allows multi-harmonic hybrid operation.

Abstract: RF (Radio Frequency, typically 500 MHz to 18 GHz) microstrip transistor test fixture which includes impedance transforming microstrip sections to pre-match the device (DUT) and wideband bidirectional signal couplers able to detect forward and reflected power waves and feed into an amplitude and phase measuring signal analyzer (such as a vector network analyzer VNA). Impedance pre-matching in the fixture allows reaching impedances (tuning) down to below 1? and power-match the power transistors (DUT), whereas the tuners alone can barely reach impedances of 5? at the DUT reference plane. Placing the couplers on transforming sections close to the DUT also allows for detection of the travelling signal waves with the smallest possible disturbance.

Abstract: An automated highly efficient “design-test-optimize” recursive loop method for experimentally optimizing embedding networks of active RF networks especially subject to wideband modulated signals, whereby the results of a matching network design are fed into the active load pull system, which synthesizes the response of the specific network design iteration and tests the transistor in real time under the emulated load conditions of the network. The weighed difference between expected and test results are used in an error function and the “design-test” loop is repeated until the error is minimized. The capacity of passive and active modulated tuners and network analysis software tools are jointly used, sharing calculated and measured data. The result of the automated optimization procedure ends into a compromise, which, if acceptable, can be processed into manufacturing with realistically expectable results.

Abstract: A passive slide screw load pull tuner structure can be used on-wafer, in millimeter-wave frequencies from 20 to 110 GHz. It uses a short external (not extended) slabline, mounted sloped and allowing direct contact with the wafer probe, thus permitting the tuning probe to come as close to the wafer probe as physically possible; this minimizes the insertion loss between tuner and DUT and, thus, generates the maximum possible tuning range of a passive electro-mechanical impedance tuner.

Abstract: Impedance tuners used in high power measurements suffer fast heating and consequently mostly linear thermal expansion of the central conductor, which has a very small mass and is thermally isolated from the slabline walls and the tuner housing. This leads to false measurements or catastrophic tuner failure (short) of either the DUT or the tuner. Gold plated INVAR and SUPER-INVAR center conductor material is preferred to traditional stainless-steel rod. The body of the airline is made of high conductivity low cost Aluminum. INVAR type alloys quasi eliminate the thermal expansion, reducing it by a factor between 10 and 40 compared to Steel. Practical tests have shown significant improvement in thermal behavior.

Abstract: Test setup and calibration method for wideband, integrated assemblies of signal couplers with single (wideband) and multi-probe (harmonic) impedance tuners using two-port and four-port network analyzers for exact wave and time-domain measurements of strongly mismatched poor directivity ultra-wideband coupler-tuner configurations.

Abstract: A test method allows investigating the dependence of microwave gain, power and linearity behavior of transistors, in which modulated RF signal is injected, as a function of source and load impedance at the signal RF carrier frequency and its harmonics as well as at the modulation (baseband) frequency, using passive programmable tuners. A calibration method generates data allowing the test setup to simultaneous and independent tune at RF and baseband frequencies without the need of on-line vector signal measurement. This allows optimizing baseband frequency impedances for nonlinear amplifier performance with modulated signal, such as ACPR, EVM, IMD etc. Baseband tuning is done using low frequency programmable impedance tuners inserted in the DC branch of the bias networks, which operate as frequency diplexers.

Abstract: High power impedance tuners suffer from intense heating of the center conductor of the tuner airline (slabline), due to dissipated RF and DC power and, in addition of high electric field between the metallic tuning probe (slug) and the center conductor, also from associated thermal expansion causing bending of the center conductor and electrical short. If the thermal expansion cannot be accommodated by structural means, the center conductor is cooled using re-circulating low loss dielectric liquid (Mineral Oil), which fills the slabline and dissipates the heat. The cooling dielectric liquid is guided through an external refrigerator and recycled back into the slabline.

Abstract: An electro-mechanical MHz range harmonic load pull tuner is made as a cascade of filter sections and independent tuning sections; the filter section includes three parallel series resonant circuits, each set including one inductor and one adjustable capacitor. The tuning section includes three parallel tuning modules; each module comprising three adjustable shunt air capacitors inter-connected using coaxial cables of appropriate length. Each capacitor is remotely adjustable to 10 or 20 values (settings); the tuner creates independently controllable impedances at three (harmonic) frequencies in octave size frequency bands between 5 and 150 MHz. An Error Function-based optimization algorithm allows impedance tuning at three frequencies independently, by optimized searching among the more than 209=512*109 possible combined tuner states. Stepper motors, drivers and control software are used to automate, calibrate and use the harmonic tuner for automated harmonic load pull measurement.

Abstract: Wideband coaxial low loss signal couplers use an electro-magnetic loop placed perpendicularly in a mantle hole of the external wall of the coaxial airline. The signal coupling factor increases with frequency thus favoring detection of harmonic components generated by the nonlinearly operated RF transistors. In order to adapt also to various power levels and associated harmonic receiver sensitivity the coupling factor can be adjusted either by controlling the penetration of the loop inside the airline cavity or by rotating the loop around its vertical axis.

Abstract: Coaxial microwave transistor test fixtures provide lowest insertion loss possible and include, as part of the input and output sections, transformer networks either in form of single stage ?/4 segments, or, for larger bandwidth, multiple step segments or ramped transitions from 50? to the impedance closer to the internal impedance of the power transistor. The transforming networks are flat or cylindrical and can be made exchangeable in order to accommodate various transforming ratios using the same fixture body and coaxial adapters. The fixtures can be calibrated using standard TRL method.

Abstract: An active digital electronic tuner (AET) uses a digital PIN diode electronic tuner, an adjustable directional coupler, two circulators and a power amplifier to create a compact load pull tuner device able of generating octave frequency band virtual reflection factors |Gamma|?1 at milli-second tuning speed.

Abstract: A compact millimeter-wave slide screw impedance tuner allows reducing to a minimum the insertion loss between the tuner and the wafer-probe. The structure of the tuner uses a 1 mm slabline and adapters, an eccentrically rotating remotely controlled wideband tuning probe and a sliding rack on which the tuning-probe is attached; the position of the rack is controlled by a permanently anchored motorized pinion. The construction method allows for maximum compactness, needed in order to be able to attach the tuner directly on the wafer-probe and minimize the insertion loss, while maintaining key advantages of electro-mechanical tuners, such as robustness, linearity, simplicity, tuning resolution and calibration and compatibility with existing load pull software and technology.

Abstract: High GAMMA disc-shaped tuning probes for high frequency electro-mechanical slide screw impedance tuners use a notch slug concept, whereby the head of the tuning probes is split in two distinct lobes in a static pre-matching configuration. The disc-probes rotate around an axis perpendicular to the axis of the slotted airline of the tuner and do not require a cumbersome vertical axis. The rotation moves the tuning lobes gradually into the slot of the airline and controls the amplitude of the reflection factor through increasing coupling. The disc-probes comprise two diametrical opposite tuning lob assemblies designed to create high reflection (GAMMA) at two distinct frequency bands, one for high end frequencies and one for low end frequencies.

Abstract: A millimeter-wave, high GAMMA on-wafer load pull system uses a tuner with extended inclined slabline (bend-line) and a manually controlled low profile pre-matching module, mounted on the bent section of the slabline next to the wafer-probe. The pre-matching module uses a mobile sliding rack and a rotating tuning probe; the rack is mounted on the slabline extension and controlled by a fixed pinion. Both the rack and tuning probe position and immersion into the slabline are controlled using sidewise mounted easily accessible manual knobs. The low profile of the pre-matching module is a crucial feature and allows integration on the extended slabline of the tuner in immediate proximity of the wafer-probe, thus minimizing any additional insertion loss and maximizing tuning range. Manual handling of the pre-matching tuning module is easy and a pre-calibration allows efficient on-wafer load pull operations.

Abstract: A passive slide screw load pull tuner structure can be used on-wafer, in millimeter-wave frequencies from 25 to 110 GHz and above. It uses special tuning probe brackets and a short slabline mounted below the tuner housing, which holds the control gear. The tuner is mounted under an angle matching the angle of the wafer-probe, is connected directly of the wafer-probe and ensures optimum tuning range.