Acconeer A111 User manual

Hardware and physical integration
guideline PCR Sensor A111
User Guide

Hardware and physical integration guideline PCR Sensor A111
Page 2 of 32
深圳市佰誉达科技有限公司 Tel: [phone] 2019-12-04
Hardware and physical integration guideline PCR Sensor
A111
User Guide
Author: Acconeer
Version 1.0: 2019-11-13
Acconeer AB

Hardware and physical integration guideline PCR Sensor A111
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2019-12-04 Tel: [phone] 深圳市佰誉达科技有限公司
Table of Contents
1 Introduction..................................................................................................................................... 4
1.1 Radar loop equation................................................................................................................. 4
1.2 Radar radiation pattern............................................................................................................ 5
2 HW Integration - Schematics .......................................................................................................... 6
2.1 Power....................................................................................................................................... 6
2.2 SPI Interface............................................................................................................................ 7
3 HW Integration - PCB..................................................................................................................... 8
3.1 Sensor ground plane................................................................................................................ 8
3.2 Sensor underfill ....................................................................................................................... 9
3.3 Integration with other components.......................................................................................... 9
3.4 A111 Decoupling capacitors ................................................................................................. 10
3.5 A111 Crystal.......................................................................................................................... 11
4 Physical Integration....................................................................................................................... 13
4.1 Radome integration ............................................................................................................... 13
4.2 Radome thickness.................................................................................................................. 15
4.3 Radome distance.................................................................................................................... 16
4.4 Impact on the radiation pattern.............................................................................................. 18
4.5 Multi-layer radome integration.............................................................................................. 20
5 Physical Integration - Lens............................................................................................................ 22
5.1 Focal distance........................................................................................................................ 23
5.2 Radiation pattern................................................................................................................... 25
5.3 FZP Lens Design................................................................................................................... 26
6 Appendix A: Materials.................................................................................................................. 29
7 References..................................................................................................................................... 30
8 Revision......................................................................................................................................... 31
Disclaimer ............................................................................................................................................. 32

Hardware and physical integration guideline PCR Sensor A111
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深圳市佰誉达科技有限公司 Tel: [phone] 2019-12-04
1 Introduction
This document aims to provide general guidelines for the hardware and physical integration of the
Acconeer A111 radar sensor. The A111 sensor is a fully integrated 60 GHz radar including the
transmitter and receiver antenna. The Tx/Rx antenna is a folded-dipole type and the E-plane and H-
plane of the antennas are indicated in Figure 1. The radiation pattern of the radar transceiver can be
found in the A111 datasheet [1]
The provided guidelines aim to optimize the radar sensor performance when integrating it into your host
product.
Figure 1 Sensor mounted on a printed circuit board (PCB). E-plane and H-plane are highlighted with blue and red
color, respectively.
1.1 Radar loop equation
Consider a signal transmitted through free space to a radar target located at distance Rfrom the radar.
Assume there are no obstructions between the radar and the radar target, and the signal propagates along
a straight line between the two. The channel model associated with this transmission is called a line-of-
sight (LOS) channel. For the LOS channel, the corresponding received reflected power from a radar
target, i.e. the signal to noise ratio (SNR), can be defined as
 

Ris the distance of the radar to the target, is the radar loop gain,,including both the transmitter and
receiver chain (two-ways signal path), is the Radar Cross Section (RCS) of the scattering object and
determines the reflected power of the object’s material. RCS depends on the roughness, size and shape
of the scattering object. Moreover, SNR depends on the sensor profile setting. A comprehensive
explanation of the sensor profiles can be found in Acconeer’s “Radar Sensor Introduction” [2].

Hardware and physical integration guideline PCR Sensor A111
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2019-12-04 Tel: [phone] 深圳市佰誉达科技有限公司
1.2 Radar radiation pattern
When characterizing the gain, we refer to the radar loop gain defined in the radar equation section.
Figure 2 shows the radar setup configuration for the radar radiation pattern measurement. The reflector
which in this case is circular trihedral corner (radius of 5 cm) is located at the far-field distance from the
sensor (1 m). The far-field distance can be determined by the aperture of the sensor and the radar target.
 

where A is the largest dimension of either the sensor or the radar target. Envelope service can be used
to collect the reflected power at the fix distance from the radar target at different rotation angle.
Figure 2 Measurement setup for sensor radiation pattern.