The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Tables of integrals

Advanced Mathematical Methods for Scientists and Engineers

This article presents a historical review of the research carried out on dielectric resonator antennas (DRAs) over the last three decades. Major research activities in each decade are highlighted. The current state of the art of dielectric-resonator-antenna technology is then reviewed. The achievable performance of dielectric resonator antennas designed for compactness, wide impedance bandwidth, low profiles, circular polarization, or high gain are illustrated. The latest developments in dielectric-resonator-antenna arrays and fabrication techniques are also examined.

Dielectric Resonator Antennas: A Historical Review and the Current State of the Art

We propose a general approach to the synthesis of cross-coupled resonator filters using an analytical gradient-based optimization technique. The gradient of the cost function with respect to changes in the coupling elements between the resonators is determined analytically. The topology of the structure is strictly enforced at each step in the optimization thereby eliminating the need for similarity transformations of the coupling matrix. For the calculation of group delays, a simple formula is presented in terms of the coupling matrix. A simple recursion relation for the computation of the generalized Chebychev filtering functions is derived. Numerical results demonstrating the excellent performance of the approach are presented.

Synthesis of cross-coupled resonator filters using an analytical gradient-based optimization technique

A design theory is described for rectangular waveguide metal insert filters that includes both higher order mode interaction and finite thickness of the inserts. Optimized design data for three- to five-resonator type filters with severaf insert thicknesses suitable for metal stamping and etching techniques are given for midband frequencies of about 15, 33, 63, and 75 GHz. Measured passband insertion losses of prototypes for mid-band frequencies of 15, 33, and 76 GHz are 0.2, 0.6, and 0.7 dB, respectively.

/pdf/optimized-waveguide-e-plane-metal-insert-filters-for-16nw3ax3wz.pdf

Optimized Waveguide E-plane Metal Insert Filters For Millimeter-wave Applications

A cross-slot-coupled cylindrical dielectric resonator antenna (DRA) is studied theoretically and experimentally. In previous papers, a cross-slot of unequal slot lengths was centered under the dielectric resonator (DR), resulting in circular polarized operation of the antenna. In the present study, the design is enhanced by setting the centers of the two slots at different positions and taking into consideration the partial independence of the slot modes from the DRA mode. Thus, circular polarization (CP) bandwidth of up to 4.7% is attained experimentally in the broadside direction. It is also shown that a largely asymmetrical structure results in a very high bandwidth, but with the tradeoff of distorted CP operation off-broadside

/pdf/offset-cross-slot-coupled-dielectric-resonator-antenna-for-1n7l4hfyew.pdf

Offset Cross-Slot-Coupled Dielectric Resonator Antenna for Circular Polarization

A design theory is described for low-insertion loss fin-line filters that includes both higher order mode propagation and finite thickness of the dielectric substrate and the metallic fins. Design data for three-resonator type fin-line filters with several substrate thicknesses are given for midband frequencies of about 15, 34, and 66 GHz. The measured insertion losses in the passband are 0.25, 0.5, and 1.3 dB, respectively, for these three frequencies.

/pdf/theory-and-design-of-low-insertion-loss-fin-line-filters-3r76jc7j8v.pdf

Theory and Design of Low-Insertion Loss Fin-Line Filters

The paper presents a rigorous full-wave analysis of propagation in corrugated and periodically loaded waveguides. The propagation constants are determined from the classical eigenvalues of a canonical matrix eigenvalue problem instead of a determinant. The entries of the matrix are computed only once per frequency point. The entire k/sub 0/-/spl beta/ diagram of a corrugated circular waveguide, a circular waveguide periodically loaded with dielectric disks, and a rectangular waveguide periodically loaded with capacitive irises are determined and compared with results of other researchers. Excellent agreement is documented in each case.

/pdf/spectrum-of-corrugated-and-periodically-loaded-waveguides-352r77yf7p.pdf

Spectrum of corrugated and periodically loaded waveguides from classical matrix eigenvalues

Improved stopband attenuation is achieved by thick strips, by reduced waveguide sidewall dimensions, and by double planar integrated circuits. In contrast to thick strips which may cause high passband insertion losses and filters with reduced waveguide dimensions which require additional tapers, double planar E-plane integrated circuit filters combine the advantages of low costs, high stopband, and low passband insertion losses. Computer-aided design of a four-resonator Ka -band double metal insert filter achieves a calculated stopband attenuation between 40 and 60 GHz of more than 50 dB, the calculated minimum passband insertion loss is 0.43 dB (measured 1.8 dB). Higher order mode excitation and finite thicknesses of the inserts are included in the calculations.

/pdf/e-plane-integrated-circuit-filters-with-improved-stopband-19atnx7lv7.pdf

Ruediger Vahldieck

Papers

Optimized Waveguide E-plane Metal Insert Filters For Millimeter-wave Applications

Offset Cross-Slot-Coupled Dielectric Resonator Antenna for Circular Polarization

Theory and Design of Low-Insertion Loss Fin-Line Filters

Spectrum of corrugated and periodically loaded waveguides from classical matrix eigenvalues

E-Plane Integrated Circuit Filters with Improved Stopband Attenuation (Short Papers)