An Introduction to Modern Ka-Band Radar Design

Key Takeaways

• Ka-band radar design gained popularity by providing merits such as compact antenna size, higher resolution, and low atmospheric absorption losses. 

• Factors such as transmitted power, antenna beamwidth, atmospheric attenuation, and physical size should be considered when selecting a radar frequency.

• Ka-band radar design is a crucial part of systems such as robust sensing, surveillance, aviation, astronomy, etc. 

Modern radar systems are utilized in applications such as smart mobility, law enforcement, aviation, astronomy, and agriculture

In application fields such as aviation, astronomy, climate, energy, agriculture, and remote sensing, the use of radars is essential. In military, industrial, and communication radar applications, higher resolution and compact-size antennas can be achieved by carefully choosing the wavelength or frequency of the electromagnetic radar wave. Lower wavelengths or higher frequency bands are preferred for high-resolution radars with compact-size antennas and other components.

Ka-band radar design has gained popularity by providing merits such as compact antenna size, higher resolution, and low atmospheric absorption losses. Ka-band radars are utilized under harsh weather conditions such as foggy or cloudy environments. In this article, we will briefly go through modern radar systems, radar frequency selection, and generalized Ka-band radar design.

Modern Radar Systems

Modern radar systems are utilized in various applications including climate monitoring, smart mobility, law enforcement, defense or military systems, aviation, astronomy, and agriculture. In all these applications, the frequency source is the main thing that determines the performance of the radar.

What Is Radar?

Radar is an electromagnetic device that detects and locates the target or parameters of the target by radiating an electromagnetic wave and using the reflected wave from the target. The principle of operation of the radar remains unchanged at any radar frequency.

Modern radars are well-known for operating in the range of 400MHz to hundreds of GHz. However, depending on the applications and space available for placing the assembly, radar frequencies are chosen. Higher frequency calls for compact-size antennas and associated systems. 

Selecting Radar Frequency 

Most radar frequencies are radio frequency bands. Radar frequencies ensure the compatible operation of radar without disturbing other radar systems. The most commonly used radar frequencies are L, S, C, X, Ku, K, and Ka. Radar frequencies are selected according to the application requirements. Other factors such as transmitted power, antenna beamwidth, atmospheric attenuation, and physical size are also considered when selecting a radar frequency.

Factors Influencing Radar Frequency Selection

The factors influencing radar frequency selection are:

Transmitted power - The transmitted power increases with wavelength. Radars operating at the wavelengths in the order of meters transmit megawatts of power, whereas millimeter wave radars limit the average transmitted power to hundreds of watts.

Physical size - The higher the frequency, the shorter the wavelength, and the smaller the antenna and other related components.

Atmospheric attenuation - The absorption and scattering of electromagnetic waves are common when they travel through the air. The atmospheric attenuation is based on absorption and scattering; both of these phenomena increase with frequency.

Beamwidth - As the beam width becomes narrower, the transmitted power and angular resolution of the radar settle to a better value. With the increase in frequency, small antennas become sufficient for narrow beams.

Generalized Radar Design

Irrespective of the frequency band, radar systems are comprised of:

1. Transceiver unit - The transceiver is Transmitter+Receiver. The transceiver includes the generation and processing of radar signals.
2. Processing unit - The signals from radar components and external devices are processed in this unit.
3. Control unit - The control system governing the radar operations is maintained by the control unit.
4. Antenna unit - Incorporates an antenna for radiating radar waves and a motor for rotating the antenna.
5. Display unit - The data from the radar and connected sensors is displayed on the radar screen.

 Let’s look at Ka-band frequency system design.

Frequency-Modulated Continuous Wave Ka-Band Radar Design

Frequency-modulated continuous wave radars are popular among the current commercial radars for their reduced size, power consumption, and cost. The performance of Ka-band radar is not degraded much by the use of frequency-modulated continuous waves. Frequency-modulated continuous wave Ka-band radar design consists of:

1. Transmitter chain - From the transmitter chain, the Ka-band waveform is produced by modulating an oscillator with the saw-tooth reference signal.
2. Receiver chain - The echo signal received by the receiver antenna is down-converted and directs the intermediate frequency signal to the data acquisition system.
3. Data acquisition system (DAS) - The digital signals received for computing the target parameters such as reflectivity, Doppler profiles, etc. are obtained from the DAS.
4. Display - The calculated target parameter is displayed on a monitor.

Ka-band radar design is a crucial part of robust sensing, surveillance, aviation, and astronomy systems. The reduced size of the antenna and other components associated with Ka-band radar systems enables this radar to expand its applications into systems with space constraints.

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. Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. If you’re looking to learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.