When selecting a filter implementation, one factor that is common across all frequencies is optimizing the size of the filter given the application and the required performance. At mmWave frequencies this can be prove to be a particularly interesting problem, given the change in the physical dimensions of the system as one moves from say 600MHz to 38GHz. 

Over time, the telephone replaced the telegraph, and now cellular and voice over Internet protocol (VoIP) technology are replacing the landline. However, as more communication is done wirelessly and over the Internet, we are becoming more interested in increased bandwidth. This is because bandwidth places a limit on how quickly we can send information through a channel such as an optical fiber or a section of the radio spectrum.

Healthcare professionals and patients rely on magnetic resonance imaging (MRI) technology to examine soft tissues and organs in the body to detect a variety of issues, from degenerative diseases to tumors, in a non-invasive manner. To do this, the MRI machine uses a strong magnetic field and computer-generated radio waves to produce cross-sectional images. Thus, the quality of the MRI depends on the uniformity of the magnetic field – even the smallest trace of magnetism inside an MRI scanner can disrupt the field and degrade the quality of an MRI image. 

To choose the right filter for your application, you'll need to evaluate filter type, identify the specific filter technology that best suits your application, and ensure the filter meets your required specifications. This post is designed to serve as a quick reference on the common terms that are used to discuss filter type, technology, and specifications.

To start, there are four key Filter behaviors that sort them into types: Low Pass, High Pass, Band Pass, and Band Stop.

Knowles Precision Devices will be at the upcoming Optical Fiber Communication (OFC) Conference, the largest global conference and exhibition for optical communications and networking professionals, March 10-12 in San Diego. For over 40 years, OFC has drawn attendees from all corners of the globe to meet and greet, teach and learn, make connections and move the industry forward.

At the show, Knowles will demonstrate broad bandwidth optical networking solutions using our latest high-performance microelectronic components.

Many microwave applications, such as repeaters, and electronic warfare equipment, require increased spectral resolution. This means these devices only need to look at a narrow slice of a given band. Filters that are optimized for the whole band, such us our planar microstrip devices, are too broadband for these applications. Likewise, traditional high Q filters, such as waveguide devices, are often too large to consider using in these types of applications.

With more than 2,000 satellites currently orbiting the Earth, and that number expected to quintuple in the next 10 years, the demand for space-ready components is exponentially increasing (Figure 1). At the same time, the technology needed to control and transmit satellite data has changed from mechanically controlled parabolic or dish technology to active electronically steered arrays (AESAs).

At Knowles Precision Devices, we support a wide variety of industries and applications with unique needs; the product catalog is constantly evolving to accommodate. We are often asked which frequencies we support. While our microwave products excel at higher frequencies, the catalog spans a wide range.

An Ideal Filter

The Ideal Filter would have unit gain (0dB) in its pass band and a gain of zero (-infinity dB) in its stop band. Between pass band and stop band there would be no indecision and would transition from 0dB to -infinity dB asymptotically. It would pass only the required frequencies without adding or subtracting anything from the signal and like a very discrete and fastidious butler we would not see it - just its perfect management of the frequencies in its care.

Around the world, 2019 was a busy year for 5G, with standards being finalized, large networks beginning 5G operations, and mobile device manufacturers releasing 5G-capable phones. Just one year after the official launch of 5G on November 1, 2018, the Global mobile Suppliers Association (GSA) identified the launch of 50 commercial 5G networks along with 328 operators in 109 countries that announced investment in 5G. Let’s look at some of the big moments for 5G from 2019.