everything RF recently interviewed Dr. Christos Tsironis who is the Owner at Focus Microwaves. Focus Microwaves is an innovative engineering company, founded on the groundbreaking work of Dr. Christos Tsironis, who introduced his first manual tuner back in 1973 and is credited with inventing most existing electro-mechanical tuner families. The cornerstone of Focus's success lies in the exceptional engineering and manufacturing capabilities of its dedicated and experienced team of engineers and technicians. These professionals have been nurtured and empowered to spearhead the development of cutting-edge technologies.
Q. Can you give us a brief history of Focus Microwaves?
Dr. Christos Tsironis: Focus Microwaves is a pioneering engineering company, built around the innovations of its founder Dr. Christos Tsironis who developed his first manual tuner in 1973 and is the inventor of most existing electro-mechanical tuner families. The success of Focus is based on the engineering and manufacturing skills of its highly motivated and experienced team of engineers and technicians, who have been trained and encouraged to develop new technologies. In addition, listening to our customers needs and insights helps us discover and develop new and measurement methods on an ongoing basis, relentlessly pushing the limits of what is possible.
From humble beginnings in 1988, Focus has become the main supplier of advanced Load Pull and Noise Tuner Systems. Our mission is to provide effective, reliable and innovative solutions for non-50 Ohm testing (Noise and Load Pull) of RF microwave transistors, thus enabling our customers to compete in the marketplace with better designs and to advance the understanding and knowledge of the field.
The Focus Microwaves Group comprises Focus Microwaves Inc., Mesuro Ltd. and Auriga PIV Tech Inc. They are All Engineering and Manufacturing Corporations based in Montreal (Canada), Cardiff (UK) and Merrimack (USA) respectively, as well as a dedicated Sales and Support office in Beijing.
Q. What are some of the key products and solutions offered by Focus Microwaves?
Dr. Christos Tsironis: Together, the three companies under the Focus Microwaves Group umbrella cover a wide range of non-50 Ohm measurement products and systems, from active and passive load pull solutions, noise characterization systems, behavioral and compact modelling solutions to pulsed IV measurements and bias tees. With our in-house engineering and manufacturing capabilities, we are able to develop our innovative products quickly and effectively, continuously bringing to market new solutions for the ever-changing demands of the RF landscape.
Q. Focus Microwaves has developed a wide range of Impedance Tuners. Can you tell us more about these products and where they can be used?
Dr. Christos Tsironis: To do load pull, one has to control the impedance (or reflection factor) presented to the device. In terms of reflection factor Γ, this is the ratio of reflected to injected power wave into the load at each frequency; assuming a two-port, Γload = <a>/<b>. <b> is created by the two-port (device under test, DUT). By controlling <a> we can control Γ.
A variable passive load is an impedance tuner. The established technology for such devices is the “slide screw tuners”; these are made of a slotted, low loss airline, mostly in form of a parallel plate airline (airline), inside which reflective probes are moved. The probes are made of metal or metallized plastic, are capacitively coupled with the central conductor and create a variable capacitive load and strong field deformation. The tuners are automated using remotely controlled stepper motors and gear. All tuner operations are described logically using motor steps (X, horizontal, Y vertical).
The maximum limit of |Γ| that can be presented to the DUT is called “tuning range”. Tuning range is important, because most microwave power transistors have low internal output impedance Ri, in the range of 1 to 3 Ohms. This corresponds to reflection factors |Γ| of 0.96 to 0.89; (VSWR between 50:1 and 17:1; VSWR = 50/Ri, |Γ| = (VSWR-1)/(VSWR+1).
In 2004 the new concept of multi- purpose tuner (MPT) [16] was introduced. This tuner uses three independent wideband probes (slugs).
A new tuner type, the “DELTA” wideband and harmonic tuners solve this problem: in these tuners, designed mainly for 5G applications (10-67GHz), the airline is short, in line and in direct contact with the wafer probe and the tuning probe is immediately adjacent to the tuner test port. This allows VSWR at DUT reference plane higher than 10:1 at 30GHz, which is enough for many 5G applications.
Q. Why are load pull measurements important? Can you tell us about the load-pull measurement solutions that you offer?
Dr. Christos Tsironis: Modern active devices in RF/micro- wave power amplifiers can deliver high output-power levels, at times over broad frequency ranges. But this requires establishing optimum source and load conditions for those active devices at as many operating frequencies as possible. Finding those optimum load conditions is possible by characterizing a device under test (DUT) while changing the impedance presented to the load at different frequencies while measuring to find the maximum output power at each frequency.
Focus offers following load pull solutions:
- Scalar load pull from 0.1GHz to 330GHz using passive tuners
- Vector load pull from 0.1 to 220GHz using passive tuners
- Hybrid Active load pull from 0.1 to 120GHz
- Active load pull solution from 0.5 to 40GHz
- Modulated load pull solution from 0.5 to 6GHz.
Q. Focus Microwaves is also known for its software tools for electromagnetic simulation and analysis. Could you tell us more about these tools and their capabilities? How do they assist engineers in the design and optimization of microwave circuits and components?
Dr. Christos Tsironis: FDCS includes several software products aimed at characterizing transistor devices. These comprise of Load pull, Noise parameters extraction, data plotting and API functionalities. Advanced utilities are available for tuner control/calibration, driver-based instrument communication, and reference plane de-embedding. FDCS incorporates advanced software routines for Scalar Load Pull, Time-domain based Vector Load Pull and Hybrid active injection Load Pull allowing the combination of active injection and passive tuning.
Q. Apart from the Impedance tuners and test systems focus microwaves also has other test and measurement ancillaries like calibration kits, test fixtures, etc. Is this also an important segment for you, what made you enter this segment?
Dr. Christos Tsironis: In an effort to provide complete measurement solutions to our customers, Focus Microwaves has developed, over time, customized accessories, which will make sure a load pull or noise test system will operate as expected. The accessories offered by Focus microwaves include TRL Calibration Kits, Low loss bi-directional couplers, test fixtures, high performance bias tees for Pulsed signal and noise parameter characterization. Similarly Focus also offers complete integration solutions for on-wafer applications.
Q. Focus Microwave sells several complete test & measurement solutions. How do you sell these solutions to customers? Is this something that they buy and install at their premise or do you customize the solution for the customers and set it up for them? Can you tell us more about the installation process and support?
Dr. Christos Tsironis: Every solution that Focus sells is customized to customers requirements. Every project involves an in-depth discussion between the customer and Focus sales and application team. All customer requirements are thoroughly evaluated and the customer is provided with a quote that best suits his requirements. Upon delivery a Focus applications engineer goes to customer site and helps in complete installation and commissioning process. The system performance is verified both in terms of mechanical integration and RF Parameters. The user is fully trained to independently perform system calibration and verification and run the final measurements.
Q. How does Focus Microwaves ensure good customer support across the globe for the sales and post-sales process?
Dr. Christos Tsironis: For all sales related questions Focus has sales partners around the world. All initial requests are handled locally via our sales representatives. To educate our customers with all our latest products and solutions we regularly schedule on site customer visits. Also Focus Microwaves is a solution partners with all leading test & measurements companies like Keysight, R&S, NI, Formfactor and MPI. Together with our solution partners we frequently schedule different seminars and webinars.
In terms of post-sales support Focus Microwaves website offer a comprehensive online support in the form of FAQ’s. Also, our application engineers are always available for by phone and if required onsite support is also provided.
Q. What does 2023 look like for Focus Microwaves group? Are there any new solutions or products on the horizon?
Dr. Christos Tsironis: D-band vector and Noise parameter extraction solutions and its easy scalability to G band; DLP, our newest active harmonic load pull solution; Advanced features in Pulsed IV and Tri-State Pulsed IV measurements and high voltage application (up to 2000V); Ultra-wide band 3F0 harmonic coaxial tuners from 5-67GHz.
About Focus Microwave
From its modest origins in 1988, Focus has evolved into the leading provider of advanced Load Pull and Noise Tuner Systems. Our overarching mission revolves around delivering efficient, dependable, and ingenious solutions for non-50 Ohm testing (Noise and Load Pull) of RF microwave transistors. In doing so, we equip our clients with the tools they need to excel in the competitive marketplace by facilitating superior designs and enhancing knowledge in the field.
