Feature: Components


Figure 3: VDI VNA extender


As any system designer knows, it can be quite diffi cult to move


sensitive and bulky T&M equipment around a production facility. Vector network analyser (VNA) manufacturers have already responded with streamlined USB-type devices that are smaller, more portable and cheaper than their benchtop counterparts; the problem is that they only operate at microwave frequencies (26.5-75GHz). To make these systems smaller, some companies are now


releasing custom modules that pair high-performance extender analysers with the new VNAs. At VDI we manufacture these extenders (see Figure 3), which can reach over 1,100GHz. For the new compact USB VNAs, the company has extended its T&M capabilities to the lower end of the THz band (400GHz), bridging the gap between low cost and high performance.


Seeing is believing At a recent microwave symposium, the extender analyser technology was tested on a patent-pending mmWave hybrid circulator (150-190GHz). Manufactured by Micro Harmonics, the new component can theoretically cover entire waveguide bands, with relatively low insertion loss and over 20dB of isolation. T is allows greater volumes of data throughput in systems operating in the upper regions of the mmWave spectrum. It has already paid dividends for Micro Harmonics, which under


a two-phase Small Business Innovation Research (SBIR) contract awarded by NASA, is developing a complete line of hybrid circulators operating in every standard waveguide band from 50-250GHz. By providing a major boost to existing T&M equipment, VDI


is using many of the advancements VNA manufacturers have developed in the lower microwave bands, which will spur more innovation and development in this higher-frequency space.


Incremental steps Another huge benefi t of new VNAs that operate at higher frequencies is the ability to generate multi-port measurements. “Typically, we have only been able to get either a one-port or


two-port measurement at a time,” said David Porterfi eld, Founder and CEO of Micro Harmonics. “Now there are VNAs that can make up to eight measurements at the same time. For companies looking to ramp up production, these VNAs greatly increase the rate of testing.”


34 September 2023 www.electronicsworld.co.uk


T is is especially important to companies that fully RF-test each


component at more than 1200 data points across a band. Micro Harmonics is really innovative in the mmWave and THz


fi elds, having designed a full line of mmWave isolators from 50- 400GHz; it is these that enable our extender analysers to operate at the very high frequencies. Having a low-cost option for VNAs used in conjunction with


mmWave extender analysers will allow developers to move equipment around more easily. Additionally, due to the small USB form factor, they can also be used in the fi eld, since many more customers are now looking for mobile setups. T ey want to take the equipment on building roofs, to perform so-called “channel sounding” to analyse a signal’s propagation.


The next frontier T ere are several challenges facing system designers looking at the next frontier of radar and communication systems. T e physics restricts building components at frequencies above 100GHz. As we move up the electromagnetic spectrum, the wavelengths get shorter, requiring the constituent parts to decrease in size. At these frequencies the parts are tiny, so even the smallest misalignment can signifi cantly degrade performance. Micro Harmonics’s Porterfi eld believes those challenges will


be overcome: “We are talking about transmitting a billion bytes of data in a single second at the D-band. T at is like catnip – so, everyone is looking for ways to make it happen sooner, rather than later.”


Figure 4: WR 28 isolators


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