We model, demonstrate, and characterize dispersion code multiple access (DCMA), and hence, show the applicability of this purely analog and real-time multiple access scheme to high-speed wireless communications. We first mathematically describe DCMA and show the appropriateness of Chebyshev dispersion coding in this technology. We next provide an experimental proof-of-concept in a 2 × 2 DCMA system. Finally, we statistically characterize DCMA in terms of bandwidth, dispersive group delay swing, system dimension, and signal-tonoise ratio.

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.

Metamaterial dispersion engineering is presented as a general concept for engineering the phase versus frequency response of microwave materials and devices. Two categories of metamaterials are considered, composite right/left-handed (CRLH) transmission line and multiscale ferromagnetic nanowire (FMNW) metamaterials. The dispersive Drude properties of CRLH metamaterials are derived and corresponding application examples are described in terms of CRLH dominant Taylor dispersive parameters: a tight broadband coupled-line coupler (phase velocity parameter), an ultra-wideband pulse position modulator transmitter (group velocity parameter), and a leaky-wave antenna based real-time spectrum analyzer (group velocity dispersion parameter). FMNW metamaterials are discussed as a double-Lorentz example of a multiscale metamaterial with unique properties, and their applications are illustrated with the example of a dual-band edge-mode isolator based on the recently discovered double ferromagnetic resonance.

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.