Focus Microwaves Group is an industry-leading engineering and instrumentation manufacturing collective headquartered in Montreal (Saint-Laurent), Quebec, Canada. Founded in 1988 by Dr. Christos Tsironis—a pioneer credited with innovating the majority of existing electro-mechanical impedance tuner architectures—the company specializes in non-50 Ohm RF (Radio Frequency) and microwave semiconductor device testing.
Focus Microwaves Group addresses the core requirement of transistor and amplifier engineering: controlling and manipulating the impedance (or complex reflection factor $\Gamma$) presented to a high-frequency component under test. The group's primary objective is providing automated hardware and software environments that enable microwave engineers to extract noise parameters, execute load pull routines, design high-efficiency power amplifiers, and characterize advanced semiconductor technologies like Gallium Nitride (GaN) used in 5G, 6G, aerospace, and satellite communication infrastructure.
The Core Challenge: Non-50 Ohm Device Characterization
Standard RF test equipment operates natively in a nominal 50-Ohm environment. However, real-world high-power and low-noise microwave transistors do not behave optimally under 50-Ohm conditions; they require specific, highly complex source and load impedances to maximize parameters such as Power Added Efficiency (PAE), output power, and linearity, or to minimize the noise figure ($F_{min}$).
To find these ideal operating points, engineers perform a process called Load Pull, where pre-calibrated source and load tuners systematically vary the complex impedance presented to the Device Under Test (DUT). Focus Microwaves Group designs the precise electro-mechanical and digital systems that synthesize, stabilize, and automate these non-50 Ohm testing conditions across frequencies scaling up into the millimeter-wave (mmW) and sub-terahertz spectra.
Technical Solutions and Core Application Methods
Focus Microwaves delivers measurement solutions across three primary methodologies:
1. Scalar Load Pull
In a traditional scalar setup, pre-calibrated electromechanical tuners are directly linked to the terminals of the DUT. Stepper motors alter internal physical probes (slugs) inside the tuner to manipulate the capacitive coupling with a central conductor, shifting the phase and magnitude of the reflection coefficient. RF power sensors and sensors tracking spectral parameters (like EVM or Adjacent Channel Power Ratio - ACPR) log the resulting output profiles to map out performance contours across the Smith chart.
2. Vector Load Pull
A more sophisticated, VNA-assisted method that incorporates directional couplers at the input and output reference planes of the DUT. By capturing raw forward ($a$) and reverse ($b$) traveling waves in real time via a Vector Network Analyzer, the system directly computes the dynamic tuner impedance. This significantly mitigates calibration drift errors and accelerates measurement processing speed because all key RF parameters are captured in a single physical sweep.
3. Active and Hybrid Active Load Pull
At higher frequencies or extreme reflection magnitudes, passive tuners introduce insertion losses that limit how close the tuner can get to the edge of the Smith chart (high voltage standing wave ratio, or VSWR). Focus Microwaves overcomes this constraint by using active load pull, which injects a coherent RF signal back toward the output of the DUT to simulate a perfect reflection ($\Gamma = 1$). A hybrid approach combines passive electromechanical tuning for fundamental matching alongside active injection for harmonic frequencies, conserving system power while unlocking complete impedance manipulation.
Core Product Portfolio
Focus Microwaves Group markets a broad suite of hardware, calibration standards, and diagnostic modules spanning from 0.1 GHz to 330 GHz:
Impedance Tuners
Fundamental Wideband Tuners (0.1 GHz to 120 GHz): Automated electromechanical coaxial tuners that utilize precise stepper-motor-driven probes to synthesize fundamental impedances over immense operational bandwidths.
Harmonic Wideband Tuners / MPT (0.2 GHz to 120 GHz): Multi-Probe Tuners (MPT) designed to independently control the fundamental frequency as well as harmonic frequencies ($2f_0$, $3f_0$). This capability is vital for designing high-efficiency architectures like Class-F or inverted Class-F power amplifiers.
Waveguide Wideband Tuners (8 GHz to 330 GHz): Specialized waveguide tuners built specifically to serve sub-mmW and terahertz testing regimes, reaching up to the D-band and G-band allocations.
Dynamic Load Pull (DLP) Systems: A modern active load pull hardware platform designed to seamlessly test CW (continuous wave) or pulsed signals up to 40 GHz, optimizing small-signal modeling and high-power verification workflows.
RAPID VT Modulated Active Tuners: Tailored specifically for wideband communications (such as 5G FR1 and IEEE 802.11ax), this platform utilizes digital transceivers to conduct modulated active load pull measurements over signal bandwidths as wide as 1 GHz.
Pulse and Bias Networks
Tri-State Pulsed-IV Systems (Auriga PIV): High-power non-linear devices often suffer from severe thermal memory and charge trapping effects (particularly in GaN materials). Focus provides pulsed I-V units capable of managing up to 2000V. These tools introduce a "tri-state" pre-pulse control scheme at the gate and drain to establish stable, repeatable trapping environments prior to taking measurements.
High-Power Bias Tees: Rated from 0.1 GHz up to 67 GHz, these accessories inject DC bias currents safely up to 200V into the high-frequency test network without introducing performance-degrading signal leaks.
Calibration and Connectivity Accessories
TRL Calibration Kits (0.3 GHz to 110 GHz): Thru-Reflect-Line (TRL) calibration kits designed to establish an absolute error model up to the DUT reference plane, removing the systematic errors of test fixtures or probe stations.
Phase Stable Assembly Cables: Coaxial interconnections engineered to maintain rigorous phase and amplitude consistency from DC up to 110 GHz under moving and dynamic thermal test conditions.
Bi-Directional Couplers: Low-loss routing components running from 5 GHz to 120 GHz, optimized to capture real-time forward and reverse traveling wave paths.
Services and Lifecycle Support
Beyond hardware delivery, Focus Microwaves Group functions as an integration partner providing comprehensive technical support models:
On-Wafer System Integration: Assisting semiconductor foundries and research labs in integrating automated tuners directly with analytical probe stations (such as MPI or FormFactor platforms) to execute bare-die screening.
On-Site Commissioning: Field application engineers deploy directly to customer cleanrooms and testing facilities to oversee system assembly, multi-instrument synchronization, and initial reference calibration.
Custom Modeling & Software Design: Providing proprietary test executive software (such as FDCS) to handle complex, automated data collection routines for scalar, vector, and time-domain analysis.
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