Wave Eyes: X-Band and K-Band Microwave Sensors from NJR

By Rob GrayAugust 17, 2016

New Japan Radio’s "Wave Eyes" range of sensing devices are aimed to help designers integrate features like moving object detection and speed measurement into their devices. Let’s discuss NJR’s Doppler modules X-band (10GHz) and K-band (24GHz) from this range in more detail.

X-Band Doppler Module - (MODEL NO. NJR4147 / MODEL NO. NJR4150 / MODEL NO. NJR4151)

The X-Band is specifically designed for motion sensing applications. The microwave sensor is an integral ingredient in security systems and automatic door openers. It can detect movements in a room, yard, or even on the other side of a wall. The Doppler module operates in the X-band frequency at 10.525 GHz and indicates movements with oscillations in its high/low output.

X-Band Doppler module consists of DRO (Dielectric Resonator Oscillator), balanced Schottky Barrier Diode mixer, and Microstrip Patch Antennas. Characteristic features, key specifications, and application ideas are covered below.


  • Operation frequency of 10.525 GHz
  • Able to detect motion through walls and windows
  • More immune to false triggers than passive infrared motion sensors
  • Active-high enables pin with internal pull-up resistor
  • Trim potentiometer on the back for manually adjustable sensitivity
  • 4-Pin SIP header for breadboard or through-hole prototyping
  • Built-in series resistor for compatibility with the Propeller microcontroller and other 3.3 V devices
  • Plated test point hole for monitoring pre-comparator signal

Key Specifications

  • Power supply requirements: regulated 5 VDC, 8 mA
  • Communication: High (3.9 V) / low (0 V) signal oscillates with motion
  • Dimensions: 1.83 x 1.87 x 0.69 in (46.5 x 47.5 x 17.6 mm)
  • Operating temp range: 32 to 131 °F (0 to 55 °C)

Application Ideas

  • Security systems
  • Automatic door openers
  • Automatic lighting
  • Nuisance animal deterrence

NJR’s K-Band Doppler module can be broadly categorized into two segments: 24 GHz Doppler Module with Pulse Operation (Single Port - NJR 4269) and 24 GHz Doppler Module including MCU (microcontroller unit - NJR 4266).

The K-Band is a low-cost, short-range sensor designed to target a varied range of applications. The microwave sensor operates at 24.125 GHz ISM band and incorporates a Gunn oscillator, mixer and a simple coupling/duplex configuration.

Salient features, specifications and market usage of the K-Band Doppler module are detailed below.

K-Band - 24 GHz Doppler Module with Pulse Operation (Single Port) - NJR 4269

The NJR 4269 is a 24GHz doppler module that detects motion using the microwave doppler effect. The main theme of NJR 4269 revolves around practical issues like facilitating low power consumption, low voltage operation and enabling a design that is cost effective in the competitive marketplace.


  • Possible to operate with pulse cycle
  • Single Port
  • Low power consumption operation
  • DRO: Dielectric Resonator Oscillator equipped
  • Integrated with built-in patch antenna
  • Fully compliant with EC Directive and FCC Certification

The main characteristic of the K-Band 24GHz Doppler Module is its minimum power consumption operation - 3V x 30mA x 0.5% (Duty: 5 usec width, 1 msec cycle) = 0.45 mW (450 uW).

K-Band - 24 GHz Doppler Module including MCU (microcontroller unit) - NJR 4266

The NJR 4266 is designed for detecting motion of low speed moving objects from a distance of 3m. The intelligent motion sensor detects movement of objects through a software embedded inside. The concept is similar to the NJR 4269, which is minimum power consumption, low voltage operation, and cost competitive design.


  • Pulse cycle operation mode for low power consumption (Target: 2 mA @ 3.3V VDD)
  • Motion sensor based on 24GHz microwave Doppler effect technologies
  • Antenna, RF circuit, IF amp, MCU, and Voltage Regulator are integrated into one small package
  • MCU Communication is available by I2C or UART interface and also stand alone operation available.
  • Multi-software Line-up (Planning)
  1. Random noise reduction for misdetection
  2. Direction discernible human-body detection of the approaching to and leaving from
  3. Presence sensing that capture the micro-vibration of the human body
  4. Position estimation detection of human body
  • All devices are compliant with EC Directive and FCC Certification.

Applications and Usage of NJR’s K-Band 24 GHz Doppler Module

  • Intrusion sensors and security systems
  • Automatic operation of taps, doors, and lights.
  • Street lights and warehouse high bay lights.
  • Automatic vending machines
  • Consumer appliances like Air Conditioner, LCD and LED Bulbs.

For more information on X-band (10GHz) and K-band (24GHz), contact a WPGA team member at 888-WPG-8881.