I have made a Mini compact Radar with display for that I have used HC-SR04 ultrasonic sensor, this sensor emit ultrasonic sound which came back to sensor after reflecting from an object, all the data visualization is displayed on 1.8" ST7735 display, if any object detect by radar it'll show in display in red line.
I have prepared a custome made PCB and order it from JLCPCB.COM to get professional touch to my project
3D files link https://www.thingiverse.com/thing:3465440
Install this library in arduino IDE before compiling https://github.com/olikraus/ucglib
Arduino nano :- https://amzn.to/2Eq3tSK
HC-SR04 ultrasonic sensor :- https://amzn.to/2SEU4vQ
SG 90 Servo :- https://amzn.to/2NG807N
1.8" ST7735 Dispaly :- https://www.aliexpress.com/item/NEW-1-8-inch-4-IO-SPI-serial-Full-Color-128x160-TFT-LCD-Display-ST7735-Module/32673683146.html