The polymerase chain reaction (PCR) (1) is being increasingly used for detecting specific DNA sequences in plants (e.g. 2, 3). The time and effort required for DNA sample preparation is often the limiting step. Although several protocols are available for this purpose (4, 5, 6, 7, 8), all involve multiple steps. Since PCR requires only a minute quantity of template DNA for successful amplification and has good tolerance toward crude DNA preparations, it might be possible to extract sufficient DNA in an appropriate buffer and use it directly for PCR. The requirements for such a buffer would be that it allows sufficient DNA extraction while at the same time not inhibiting the

Arbitrary control of terahertz (THz) waves remains a significant challenge although it promises many important applications. Here, a method to tailor the reflection and scattering of THz waves in an anomalous manner by using 1‐bit coding metamaterials is presented. Specific coding sequences result in various THz far‐field reflection and scattering patterns, ranging from a single beam to two, three, and numerous beams, which depart obviously from the ordinary Snell's law of reflection. By optimizing the coding sequences, a wideband THz thin film metamaterial with extremely low specular reflection, due to the scattering of the incident wave into various directions, is demonstrated. As a result, the reflection from a flat and flexible metamaterial can be nearly uniformly distributed in the half space with small intensity at each specific direction, manifesting a diffuse reflection from a rough surface. Both simulation and experimental results show that a reflectivity less than −10 dB is achieved over a wide frequency range from 0.8 to 1.4 THz, and it is insensitive to the polarization of the incident wave. This work reveals new opportunities arising from coding metamaterials in effective manipulation of THz wave propagation and may offer widespread applications.

We report on the design, fabrication, and measurement of a triple-band absorber enhanced from a planar two-dimensional artificial metamaterial transmission line (TL) concept. Unlike previous multiband absorbers, this implementation incorporates fractal geometry into the artificial TL framework. As a consequence of the formed large LC values, the utilized element is compact in size, which approaches λ 0 /15 at the lowest fundamental resonant frequency. For independent control and design, a theoretical characterization based on a circuit model analysis (TL theory) is performed and a set of design procedures is also derived. Both numerical and experimental results have validated three strong absorption peaks across the S, C, and X bands, respectively, which are attributable to a series of self-resonances induced in the specific localized area. The absorber features near-unity absorption for a wide range of incident angles and polarization states and a great degree of design flexibility by manipulating the LC values in a straightforward way.

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Abstract-The theory and design of a new family of multifrequency monopole antennas by smartly loading a set of complementary metamaterial transmission line (CMTL) unit cells are investigated. The distributed CMTL elements, epsilon negative (ENG) or double negative (DNG) through incorporating additional capacitive gaps, contain a Koch-shaped extended complementary single split ring resonator pair (K-ECSSRRP) etched on the signal strip. The K-ECSSRRP features dual-shunt branches in the equivalent circuit model, rendering a distinguished resonator with dual zeroth-order resonant (ZOR) modes. By smartly controlling the element layout and loading different numbers of unit cells, ten antennas covering different communication standards (GSM1800, UMTS, Bluetooth, DMB and WIMAX) are designed and four of them are fabricated and measured. At most of operating frequencies, the antennas exhibit impedance matching better than −10 dB and normal monopolar radiation patterns. Numerical and experimental results both confirm that the single-cell or dual-cell ENG and DNG CMTL-loaded monopoles exhibit almost identical dual ZOR modes. Moreover, the loaded elements also contribute to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. These antennas are compact and the multiple operating bands can be arbitrarily engineered, enabling an alternative and easy avenue toward monopoles with multifunction and high integration.