During the first-ever virtual Menlo Micro Switch Summit, Knowles Precision Devices joined John Richardson, founder and president of X-Microwave, and Tom Clickenbeard, applications engineer at Menlo Microsystems, to give a presentation on Prototyping Using X-Microwave’s XM-Blocks with Knowles Precision Devices RF Filters and MEMS Switches.

As early adopters of beamforming technology in the 1960s, aerospace and defense organizations have a lot of experience using the initial large-scale active electronically scanned arrays (AESAs) for military radar tracking applications. But these arrays aren’t as convenient for some applications today as the operational frequencies of the targets of interest for many military applications are increasing. This means the wavelengths of the signals that need to be monitored are getting shorter and these radar applications need denser arrays since antenna spacing needs to be set at one half the wavelength. For example, at 25GHz, the wavelength in free space is approximately 12mm (0.47”), leading to half-wave spacing for antennas of 6mm (0.24”). Also, as arrays become denser, the new challenge for RF system designers is avoiding interference in these tighter spaces, especially when transmitting signals.

According to the U.S. Bureau of Transportation Statistics, 2020 was the fifth consecutive year of growth in electric vehicle (EV) sales, and the demand is growing. Based on the first quarter numbers, the Bureau anticipates 2021 sales are on a path to surpass last year’s. 

Spectral efficiency, or bandwidth efficiency, tells us about the channel capacity over a 1Hz bandwidth. It is a measure of the efficiency of a physical layer protocol when it comes to utilizing the spectrum available. To understand how spectral efficiency is calculated, it’s first important to understand the Shannon-Hartley Theorem in the context of 5G mmWave applications (which we discussed in an earlier blog post).

In electric vehicle (EV) applications, filter capacitors are a special type of component commonly used as input and output capacitors. Also known as noise suppression or electromagnetic interference (EMI) filters, these particular capacitors act to remove noise and other unwanted signals on the line. On the high voltage alternating current (AC) side of a system, the capacitors often provide EMI filtering, whereas on the direct current (DC) side of a subsystem, they serve to smooth ripple components of the AC and filter out noise.

Looking back, 2020 was a year full of big changes regarding how RF spectrum is allocated in the US. Led by the Federal Communications Commission (FCC), multiple portions of the spectrum ranging from the C band to the V band were either opened to new uses and/or auctioned to new users throughout the year. These changes are driving a variety of new opportunities for wireless device manufacturers and broadband and cellular carriers, which is resulting in a range of exciting new challenges for RF technology vendors to help solve. 

One of the things all technical disciplines excel at is creating terminology that can trip up those who are not accustomed to speaking the language every day. Take the title of this article for example. These three words sound similar and are definitely inter-related, but they are not inter-changeable.

While 2020 has presented its fair share of challenges, it has also given us a chance to innovate on how we can help customers address some of the biggest issues they face – from addressing bandwidth and quality constraints to delivering new filtering and capacitor technologies. So, as the year comes to an end, we hope you have a little time to relax and re-read some of your favorite blog posts or maybe catch-up on some of the best content you may have missed. We hope these posts will bring you some holiday cheer, or at least provide some ideas and insights to use for a successful 2021.

In our last article about electric vehicles (EV), we talked about using DC link capacitors as an intermediary buffer in power converters. Today’s topic covers another useful power module component – the snubber capacitor. Snubbers are energy-absorbing circuits used to protect electronics from voltage spikes and transients caused by turning a switch from the On to Off state. Opening a switch intrinsically induces a high voltage across the device, and the snubber provides an alternate flow path for the excess energy to be absorbed by the snubber capacitor and dissipated by a resister or other load.

At any given time, there are a multitude of signals at a variety of frequencies streaming all around us. Each device that relies on receiving the proper RF signals such as televisions, radios, radars, medical devices, and cell phones, requires some level of filtering. While all filters have the same basic job – remove unwanted or out-of-band signals – the specific job requirements of each filter vary depending on the RF architecture used and the needs of the final device.