In this chapter, we discuss various circuit and antenna design issues for implementing ambient backscatter transmitters and receivers. First, we provide an overview of antenna which is crucial for ambient backscatter communication systems (ABCSs) to receive and backscatter signals. Then, ambient backscatter transmitter circuits including modulators, energy harvesters, and micro-controllers is discussed. Following this, we discuss ambient backscatter receiver circuits including interference cancelers, diversity combiners, and maximum-likelihood (ML) detectors. Finally, some open issues for realizing low-power and hyper-connectivity vision in the Fourth Industrial Revolution era are described.