Posted by: admin.elkay November 27, 2020 No Comments

Types of Tuners

Passive Tuners

Focus provides the deepest portfolio of wideband fundamental and harmonic passive tuners. Passive impedance tuners generate controllable reflection factor (Impedance) across the smith chart over a given frequency range. Focus uses two basic technologies:

  1. From 100MHz to 110GHz we use the slide screw technique in which a reflective probe is inserted into a low loss slotted transmission line.
  2. For frequencies from 10MHz to 170MHz  we use a lumped element technology, whereby variable capacitors are connected with optimized lengths of coaxial cable.

Most Focus Passive Tuners use long lasting RF probes which are designed for optimal tuning accuracy and are free of spurious resonances. The combination of multiple probes provide ultra wideband coverage in one single tuner. All Focus Passive Tuners are LAN controlled and include on-board impedance synthesis firmware.

Active Tuners

Active load pull tuning is, because of limited tuning range of passive tuners, additionally reduced by fixture and probe insertion loss, the only method allowing test engineers to reach up to  |Γload|=1 (RDUT=0Ω) to match any DUT at its reference plane. In closed loop active tuning, part of the extracted RF power from the DUT is amplified and fed back into the DUT output port, creating a virtual load.

Since the re-injected power can be higher than the original extracted power, Γ can be >1, meaning that insertion loss can be compensated. Using two (or more) synchronized (coherent) sources allows open-loop active (and harmonic) tuning; in fact the loop here is also closed, but, instead at RF, it is closed at IF synchronizing reference.

Focus offers also active source pulling technology, based on the Gamma Boosting Unit (GBU) and several associated techniques. Active load pull requires high power feedback amplifiers. Combining with pre-matching passive wideband (CCMT) or harmonic (MPT) tuners, in a Hybrid configuration, allows reducing the PA requirements by a factor of 10. The RAPID electronic active tuner technology, developed by MESURO, allows high speed load pull (50 points/second), 100 MHz modulated signal as well as hybrid and harmonic tuning.

Manual Tuners

Focus offers a complete range of manual tuners. The MMT series use the same RF technology and precision as a comparable automatic tuner.

They are available in octave and multi-octave bands between 400 MHz and 18 GHz and provide high VSWR at DUT reference plane with a high reliability.

For harmonic tuning requirements, the MMT series can be enhanced, referring to as option –H2 and –H23, using a similar concept as Focus’ harmonic rejection tuners (PHT).

Low Frequency Tuners

The low frequency tuners are a unique product technology using MPT algorithms for low frequency wideband tuning. Three or more cascaded tuning sections use series transmission cables and parallel rotary capacitors.

The length of the cables and number of tuning sections are optimized for maximum tuning range over a given bandwidth. HLFT tuners use 6 tuning sections allowing second harmonic frequency tuning.

A multi-band, electro-mechanical programmable impedance tuner for the frequency range between 10 and 200 MHz uses cascades of three or more continuously variable mechanical capacitors interconnected with sets of low loss flexible or semi-rigid cables; for each frequency band a different set of cables and capacitors are used. The cables and/or variable capacitors inside each tuning block are switchable manually or remotely. Multi-section variable capacitors are also used. Instantaneous impedance tuning is effectuated by changing the state of the capacitors using electrical stepper motors. The tuner is calibrated using a vector network analyzer and the data are saved in the memory of the control computer, which then allows tuning to any user defined impedance within the tuning range. Reflection factor values between O and higher than 0.9 can be obtained using this tuner at all frequency bands.

Rapid VT

Focus Microwaves’ RAPID digital tuner technology is now available for very wideband communication signals, supporting the latest 5G FR1 and IEEE 802.11ax standards. This new architecture leverages the raw performance of National Instruments PXIe-5841* PXI Vector
Signal Transceiver.

The Rapid VT, utilizes two PXIe-5841 VSTs to make a VNA architecture with up to 1GHz active load pull bandwidth capability.

The system solution provides a flexible load pull test platform that can be used to test the latest high bandwidth and high modulation cellular standards such as 1024QAM 802.11ax but can also be configured for fast load pull and s-parameter measurements. This opens up the possibility of using this system in all parts of the design cycle, from initial device characterization, to MMIC or PA design, design verification testing and ultimately to product testing in the factory.

Key Features

  • Supports the latest 5G FR1 and IEEE 802.11ax standards
  • up to 1GHz active load pull bandwidth capability
  • Test the latest high bandwidth and high modulation cellular standards such as 1024QAM 802.11ax
  • This system can be used in all parts of the design cycle
    • Initial device characterization
    • MMIC or PA design
    • Design verification testing
    • Product testing in the factory.