In this paper, a fully synthesizable all-digital transmitter (ADTX) is first proposed. This transmitter (TX) uses Cartesian architecture and supports wide-band quadratic-amplitude modulation with wide carrier frequency range. Furthermore, the design methodology for ADTX and corresponding bandpass filter is discussed. This TX is synthesized with digital register transfer level-graphic database system flow, and can be easily implemented in any standard CMOS technology. An exemplary TX is synthesized by TSMC 28-nm standard cell library with extremely small area (0.0009 mm2) and supports carrier frequency as high as 6 GHz with excellent error vector magnitude (<;-30 dB). To the best of the authors' knowledge, this is the first work on a fully synthesizable design of RF transistors, allowing easy technology migration and portability.

Metamaterials are materials typically engineered with novel or artificial structures to produce electromagnetic properties that are unusual or difficult to obtain in nature. Because of their promise to provide engineerable permittivity, permeability, and index of refraction, metamaterials have drawn broad interest and have led to possible utilization in many electromagnetic applications from the microwave to optical regime, especially for the radiated-wave devices. This paper presents a detailed review upon the most recent research efforts associated with those metamaterial-based small antennas. They are discussed and classified in several different categories such as the antennas based on dispersion engineering, metaresonators, and metamaterial loadings. Some practical difficulties or limitations for the development of metamaterial-based small antennas are pointed out and the possible approaches to resolve these problems are also illustrated. A wide variety of antenna examples are included to facilitate the understanding for general readers.

This paper gives a basic review and a summary of recent developments for leaky-wave antennas (LWAs). An LWA uses a guiding structure that supports wave propagation along the length of the structure, with the wave radiating or “leaking” continuously along the structure. Such antennas may be uniform, quasi-uniform, or periodic. After reviewing the basic physics and operating principles, a summary of some recent advances for these types of structures is given. Recent advances include structures that can scan to endfire, structures that can scan through broadside, structures that are conformal to surfaces, and structures that incorporate power recycling or include active elements. Some of these novel structures are inspired by recent advances in the metamaterials area.

In this paper, the evolution of the composite right/left-handed (CRLH) leaky-wave antennas (LWAs) yielding several novel CRLH LWA is reviewed. Starting with the concept of CRLH LWAs, the concave and convex passive CRLH LWAs are discussed along with the conformation effects in each case and a dispersion engineering method is introduced to compensate for the conformation effect to refocus the main radiation beam. Next, planar and conformal varactor-based electronically controlled CRLH LWAs are reviewed. In the planar case electronic beam steering and beamwidth controlling are discussed while in the case of conformal version electronic radiation aperture selectivity as well as electronic beam focusing is discussed. Finally, a dual polarized CRLH LWA is presented which is a balanced four-port coupled CRLH LW-TL that conserves its CRLH nature under both common-mode and differential-mode excitations but with two orthogonalE-planes resulting in two orthogonal polarizations for the radiated fields.

Over the past half-decade, the fundamental physical properties of left-handed(LH) metamaterials (MMs) have been established both theoretically and experimentally,and several novel MM-based microwave applications with unique characteristics have already been proposed. This paper provides a recall of the main properties of MMs and an overview of their demonstrated applications and concepts. Moreover,it suggests numerous potential future applications and points out important challenges to meet to design MMs for the next generation of microwave and optical devices.