Dmitry Kholodnyak

Broadband digital phase shifter based on switchable right- and left-handed transmission line sections

A novel approach to design digital phase shifters with the operational bandwidth extended to one octave is presented. An original design of the broadband phase shifter based on switching between transmission lines (TLs) with positive and negative dispersions is considered. An artificial TL with the negative dispersion was implemented as a quasilumped-element coplanar structure using a multilayer technology. The simulated and measured performance of the 180/spl deg/ phase shifter is presented.

Tunable Metamaterials for Controlling THz Radiation

Remarkable progress in terahertz (THz) sources and detectors is followed by the necessity of manipulating of terahertz radiation. Since natural materials can not perform efficient interaction with THz radiation, artificial structures called metamaterials are designed to overcome “THz gap” in this area. A variety of tunable metamaterials using different methods of control are presented and discussed in this review paper.

Design of quasi-lumped-element LTCC filters and duplexers for wireless communications

Multilayer integrated circuits using the low temperature cofired ceramics (LTCC) technology are considered as applied to design of microwave filters and duplexers for wireless applications. Different structures of miniature LTCC filters based on quasi-lumped-element resonators are suggested with a special emphasis to filters with additional transmission zeros. Original design of LTCC duplexer for IMT-2000 handsets is presented.

3D Antenna for UHF RFID Tags with Eliminated Read-Orientation Sensitivity

An original design of 3D antenna for passive UHF RFID tags is presented. Tags using the proposed near omnidirectional antenna are characterized by almost eliminated read-orientation sensitivity as compared to conventional tags based on planar dipole antennas. As a result the novel tags placed on the cardboard box corner can be read independently on their orientation with respect to reader antennas with two orthogonal (linear or circular) polarizations

Electronically controlled phase shifters based on right/left-handed transmission lines

Novel phase shifter structures have been suggested, simulated, and designed. The phase shifters are based on a connection of transmission line sections with positive and negative dispersion. Use of a combination of such sections allows designing miniature microwave devices operating in a wide frequency range. Different phase shifter structures are suggested: tuneable phase shifters based on ferroelectric films and a switchable channel phase shifter using multilayer ceramic technology.

Enhancement of inductance Q-factor for LTCC filter design

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.

A Compact Bandpass Filter Based on Right- and Left-Handed Transmission Line Sections

A new type of a compact second-order bandpass filter (BPF) with two transmission zeros based on transversal signal-interference technique is proposed in this letter. Unlike other transversal filters published, the proposed structure is composed of artificial right- and left-handed transmission lines, instead of traditional distributed transmission line sections. Such an approach is not only helpful in size reduction, but also promising for frequency-asymmetrical stopband performance achievement. Design equations and guidelines to adjust filter performance are provided in the letter. To validate the proposed design approach, a two-pole BPF was designed, fabricated using multilayer liquid crystal polymer (LCP) technology and measured.

Applications of Right/Left Handed and Resonant Left Handed Transmission Lines for Microwave Circuit Design

Additional degrees of freedom in a design of miniature microwave devices can be provided by a combination of right-handed (RH) and left-handed (LH) transmission lines (TL), which differ in dispersion characteristics. We present some examples of such devices: planar resonator and filter with suppressed spurious response as well as a miniaturized matched balun and broadband digital phase shifters. Whereas these structures follow the right/left-handed TL approach, it is also possible to implement left-handed structures by following the resonant type approach, i.e. by using split rings resonators or complementary split rings resonators. Examples to illustrate the possibilities of this approach are also presented

Application of sandwich multilayer technology to MICs design

The sandwich multilayer technology as applied to design of microwave integrated circuits (MICs) is considered for the first time. Potential benefits for microwave applications are discussed. Implementation of various passive MIC components as sandwich multilayer structures is demonstrated. Design of a miniature bandpass filter and directional couplers for telecommunications is presented.

Tunable Dual-Band Microwave Devices based on a Combination of Left/Right-Handed Transmission Lines

Metamaterial transmission lines can be realized as a combination of transmission line sections with positive and negative dispersion. Such lines, which are also known as right- and left-handed transmission lines, exhibit different dispersion characteristics. Compared to homogeneous networks, the use of cascaded line sections gives additional degrees of freedom for improving the performance of microwave devices. For the design process, LC-equivalents of the right- and left-handed transmission line sections are used. This facilitates the consideration of tunable capacitors, e.g., varactor diodes, to provide frequency tuning of the devices. At the same time, the geometrical dimensions of the devices can be drastically reduced. This paper presents the results of simulation and experimental investigation of a miniature rat-race-ring and a dual-band filter free of spurious response, both manufactured as fully-integrated ceramic multilayer modules based on Low-Temperature Co-fired Ceramics. The design of tunable versions of these devices is also discussed.