In this article, a low cost ink-jet printed millimeter-wave RF front-end for low-complexity Gigabit-datarate backscatter communications was designed, fabricated and measured. The RF front-end consists of a microstrip 5×1 series-fed patch antenna array and a single E-pHEMT transistor, supporting a plethora of modulation formats, including binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), and quadrature amplitude modulation (16-QAM). The circuit was additively manufactured using inkjet printing with silver nanoparticle (SNP) inks on a flexible liquid crystal polymer (LCP) substrate. A mmWave transceiver was also designed in order to capture and downconvert the backscattered signals and route them for digital signal processing. A bit rate of 2 Gbps of backscatter transmission is demonstrated at millimeter-wave frequencies 24-28 GHz, expanding the potential of backscatter radio as an ambitious low-energy, low-complexity communication system for future IoT devices. By pushing the circuit complexity to a central station/access point, the radio’s footprint is minimized, which allows additive manufacturing, resulting in significant implementation savings and compatibility with flexible platforms. The wideband operation of these systems will enable broadband wireless transmission with less than 0.17 pJ/bit front-end consumption at 2 Gbps and combined with sensing with low-power sensors and can be integrated with wearables for challenging mobile applications in 5G and the Internet of Things (IoT).