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K-Band Frequency: Advantages and Applications

Published Date
Author Cadence PCB Solutions

Key Takeaways

  • According to IEEE, the frequency range from 18 to 27 GHz is signified using the letter K and is called the K-band frequency. 

  • Law enforcement authorities use the K-band frequency for their radar systems due to its high-performing characteristics.

  • The rain fading susceptibility of the K-band frequency is less than the Ka-band frequency but more than the Ku-band frequency. 

Collision avoidance systems in vehicles

The K-band frequency is used in collision avoidance systems in vehicles

There are always limitations involved with advanced modulation techniques. Beyond a point, modulation is not a practical solution for achieving spectral utilization efficiency. Advanced modulation techniques support high point-to-point data rates, bandwidth sharing, and the reuse of frequencies. However, accessing higher frequency bandwidths becomes necessary to provide sufficient transmission capacity for wireless networking systems.

In radar and satellite communication applications, bandwidth is in the range of 18-27 GHz. This frequency range corresponds to the K-band frequency. In this article, we will explore the advantages, disadvantages, and applications of this frequency.

High-Frequency Bandwidths

There is great demand for point-to-point and aggregate bandwidth in wireless networking systems. Two methods that can help in meeting bandwidth requirements are:

  1. Advanced modulation techniques

  2. Utilizing higher frequency bandwidths

Higher frequencies help establish high spectral utilization efficiency when advanced modulation techniques hit their limitations. With the growing consumer use of cellular networks and smart portable devices, the demand for increasing transmission capacity gains momentum. In wireless communication applications, higher frequency portions of the electromagnetic spectrum are allocated for radar, satellite, and astronomical purposes. Commercial wireless point-to-point microwave communication systems rely on the 18-30 GHz frequency range, widely known as K-band and Ka-band frequencies. 

What Is K-Band Frequency?

According to the IEEE, the frequency range from 18 to 27 GHz is the K-band frequency. The wavelength of the K-band frequency ranges from 1.7 to 1.1 cm. In the electromagnetic spectrum, the K-band frequency lies between the Ku-band and Ka-band. The K-band frequency includes the peak resonance frequency of water vapor, i.e., 22.24 GHz, which makes this band unsuitable for long-range transmissions.

Advantages of K-Band Frequency

K-band frequency offers good short-range, high throughput, and high resolution. Some other advantages of employing K-band frequency include:

  1. The position between the Ku-band and Ka-band makes the K-band frequency support throughput higher than the Ku-band and lower than the Ka-band. 

  2. The rain fading susceptibility of K-band frequency is less than the Ka-band, whereas it is more susceptible than the Ku-band. 

  3. The antenna size utilized for K-band applications is more petite than Ku-band antennas and larger than Ka-band antennas.

Disadvantages of Utilizing K-Band Frequency

The K-band frequency is known for false alerts. The percentage of false alerts received is so high that many engineers don’t use the K-band frequency to avoid false positives. With K-band radars, it is important to use superior false alert filtering, which adds to the overall cost of the project. 

K-band radars are difficult to detect at long distances compared to X-band radars. This shortens the allowed time to react for the radar detector user. Another disadvantage of K-band frequency usage is the high atmospheric attenuation, which prevents its application in long-distance communication systems. 

Applications of K-Band Frequency

K-band frequency is best-suited for short-range communication. Apart from law enforcement radar systems, there are non-law enforcement applications of K-band frequency such as automatic door openers, collision avoidance systems, and blind spot monitoring systems in vehicles.

The X-band, K-band, and Ka-band are the three frequency bands that belong to radar waves. In the USA, these are the frequencies at which police radars operate. Law enforcement authorities adopt the K-band frequency due to its high performance. Law enforcement radar commonly uses 24.125 GHz and 24.15 GHz in the K-band frequency. 

Emerging K-Band MMICs

Even with the disadvantages listed above, K-band frequency is used in speed and safety radars. There are several other applications that utilize amplifiers and local oscillators that operate at K-band frequency.

For such applications, K-band monolithic microwave integrated circuit (MMIC) technology is an emerging trend that helps realize K-band power amplifiers and low noise amplifiers on a small die with reduced costs, ease of mass production, and high reliability. K-band MMICs are employed in local-multipoint distribution services (LMDS), digital point-to-point radio services, and fixed satellites.

K-band MMICs are an exciting development for K-band frequency applications, offering improved output power levels. Cadence’s suite of PCB design and analysis software can assist you in designing radar and satellite communication systems utilizing various frequency bands, including the K-band frequency. Cadence offers system analysis products that address front-to-back K-band MMIC development with superior design entry/management, RF circuit simulation, EM/thermal analysis, and system co-simulation/verification for commercial wireless applications.

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