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Ka-Band Radar

Published Date
Author Cadence PCB Solutions

Key Takeaways

  • The advantages of Ka-band frequency applications are their wide bandwidth, short wavelength, and high resolution.

  • A reduction in the size of the antenna makes the Ka-band frequency suitable for mobile applications. 

  • Ka-band radars use 3 different frequencies: 33.8 GHz, 34.7 GHz, and 35.5 GHz.

Radar

The Ka-band is well-known for its effectiveness in radar applications

Radars are vital instruments used to forecast weather, measure the speed of vehicles, measure the properties of oceans and atmosphere, observe insects and birds, and track and detect ships, aircraft, and spacecraft.

There have been considerable advances in radar technologies over the years. Today, radar technologies utilize frequencies ranging from 5 MHz to about 130 GHz. Radar frequencies can be classified as HF and VHF-band, UHF-band, L-band, S-band, C-band, X-band, Ku-band, Ka-band, V-band, and W-band. In this article, we will focus on the features of Ka-band radar.  

Ka-Band Frequency and Its Advantages

The Ka-band is a sub-classification of the K-band present in the electromagnetic spectrum. The Ka-band stands for K-above and is comprised of 27 GHz to 40 GHz frequency. The wavelength is between 1.1 cm to 0.75 cm. The advantages of Ka-band frequency applications are:

  1. Wide bandwidth - The bandwidth of the Ka-band is 5 times that of the C-band and twice that of the Ku-band. 

  2. Short wavelength - The short wavelength of the Ka-band makes the applications incorporate smaller components in the hardware, including the antenna.

  3. High resolution - The short wavelength of the Ka-band frequency leads to high resolution and can be applied in close-range radars. 

Features of Ka-Band Applications

The Ka-band frequency is often used in communication, radar, speed detection, and weather forecasting. There are some features that are inherent to Ka-band frequency, including:

  • Size of the antenna - The Ka-band frequency range is higher than the C-band and Ku-band, which is why it requires smaller antennas to receive and transmit. The cost of the antenna drops with size. The reduction in the size of the antenna and other components makes the Ka-band frequency suitable for mobile applications. 
  • Focused power - The Ka-band offers more focused power. The effective isotropic radiated power (EIRP) of the Ka-band spot beams at the beam center is higher than the Ku-band. The Ka-band provides high throughput for the bandwidth, thus bringing down the price per MB and cost of the spectrum. 
  • Frequency reuse - The Ka-band enables the reuse of frequency. When there are multiple spot beams in a service area, several beams already in service can be reused, thereby increasing the capacity of the application system. 

Ka-Band Radar Applications

The Ka-band is well-known for its effectiveness in radar applications. Ka-band frequencies are widely used in airborne radars. They are seen in interferometric radars used for civil security applications. The reduced antenna size makes the Ka-band the favorite radar frequency in spacecraft. The reduction in the overall mass of the system, ease of instrument accommodation due to space-saving, and reduction in the total cost of the system make the Ka-band frequency the most popular electromagnetic spectrum band for radar applications.

The most extensively used Ka-band frequency radar is the one employed in the law enforcement sector. Advanced police radars using Ka-band frequency are less prone to false alarms. 

Ka-Band Frequency Detection

The Ka-band frequency is the hardest frequency to detect. Ka-band radars use 3 different frequencies: 33.8 GHz, 34.7 GHz, and 35.5 GHz. Lower quality radar detectors are less sensitive to Ka-band frequencies and, most of the time, they miss the signals. However, high-end radar detectors can detect Ka-band law enforcement radars.

Let’s look at one specific application of Ka-band radars.

Ka-Band Doppler Radars

Microwave doppler radars using Ka-band frequency have gained popularity in healthcare systems. Ka-band doppler radars offer health care monitoring and detection without contact. Some of the healthcare applications of Ka-band doppler radars include the detection of humans trapped in earthquake debris, physiologic movements, and cardiopulmonary monitoring. Ka-band doppler radar is excellent at detecting human heartbeat, acoustic signals, and respiratory signals.

The advantages of Ka-band doppler radar can be summarized as:

  1. Ka-band frequency is not as crowded as low-frequency bands. The sparsely crowded Ka-band frequency is less vulnerable to interference. 
  2. The short wavelength of the Ka-band frequency spectrum is extremely sensitive to small displacement. The phase modulation generated in Ka-band radar for the same displacement is larger than in lower frequency bands. 
  3. The size of the antenna is very small and can be incorporated into an integrated chip.

Ka-band radar plays a pivotal role in law enforcement, healthcare, and weather forecasting applications. Systems with space constraints are beginning to recognize Ka-band radar systems for their compactness and lightness, and the use of this radar will continue to expand. Luckily, Cadence can assist you in developing Ka-band frequency radars. Cadence’s AWR software can support you in radar simulations with detailed analysis of RF-front end components. 

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