A metamaterial is a composite material that has attracted the attention of researchers since the late 1990s-early 2000s. This material contains an artificial periodic structure, which modifies its permittivity and permeability and, thereby, makes it possible to control the dispersion, refraction, and reflection of electromagnetic waves in the metamaterial. Analytical and experimental studies of the properties of metamaterials, as well as their applications, cover a wide frequency range from radio waves to the visible range. In recent years, considerable progress has been made toward the application of these materials in the microwave range (1–100 GHz). Works on development and application of metamaterials in the microwave range published over the last 8–10 years are reviewed. Artificial transmission lines as 1D metamaterials are discussed. Resonators, filters, and phase shifters based on the “metamaterial philosophy” are considered. Special attention is given to the application of metamaterials in the antenna technology.

An enhancement technique of quasi-lumped inductance Q-factor is proposed in order to improve loss performance of LTCC filters. Effectiveness of the technique developed is demonstrated by experimental characteristics of a 3-pole bandpass LTCC filter with reduced in-band insertion loss. Figure of merit of a filter is introduced as a universal characteristic that allows comparison of different filters by means of design effectiveness.

The commutation quality factor (CQF) is suggested as a generalized criterion of the material tunability and its loss factor. The figure of merit of a switchable device is uniquely determined by the CQF. From this point of view the CQF is used as a working tool for optimization of the microwave devices. A comparison between analog and digital ferroelectric phase shifter was performed using the CQF as a criterion. Theoretically was predicted that a digital phase shifter based on lumped tunable ferroelectric capacitors can be designed with minimal achievable insertion loss. As an example, the 180 reflection type phase shifter is discussed.

In this paper we present the design procedure of HTS bandpass filters on sapphire substrate. The filter with 0.4% fractional bandwidth in S-band was designed using an effective CAD tool, based on spectral domain approach. The filter is based on hairpin resonators exhibiting unloaded Q up to 43000 at T=77 K. The anisotropy of the dielectric permittivity of sapphire substrate and the YBCO film contribution in the propagating characteristics have been taken into account. Substrate characteristics and YBCO film model parameters were extracted from microstrip and hairpin resonator measurements. These parameters were used in the filter simulation procedure.

Radio-frequency identification systems used for the remote diagnostics of diseases and contactless monitoring and assessment of human health are reviewed. The propagation of electromagnetic waves inside a biological medium and along interfaces between different media, as well as the problem of telemetry data acquisition from implanted systems or system on the human body surface using wireless sensors, is considered. Emphasis is on radio-frequency identification systems that use far-field electromagnetic radiation, since they are necessary in emergency situations to find injured people in hard-to-reach places and assess the state of emergency response workers.