Design-Based Research (DBR) is a relatively new intervention method investigating educational designs applied to real-life settings, and with a dual purpose to develop domain theories and to develop the design, iteratively. This paper is an integrative review, which draws on literature and empirical projects to identify and discuss critical elements in DBR, in particular when doing research in ...

Planar antennas based on tightly coupled dipole arrays (also known as a current sheet antenna or CSA) are amenable for use as electronically scanned phased arrays. They are capable of performance nearing a decade of bandwidth. These antennas have been demonstrated in many implementations at frequencies below 18 GHz. This paper describes the implementation using a relatively new multi-layer micr...

A tunable channel-drop filter as essential component for the wavelength-division-multiplexing optical communication system has been demonstrated, which is based on polymer waveguide Bragg reflectors. For an ordinary Bragg reflector, the filtered signal is reflected toward the input waveguide. Thus an external circulator is required to separate the filtered signal from the input port, though it ...

Convoluted elements on a frequency selective surface (FSS) allow for low to be contained in physically smaller unit cells. Smaller cells give the FSS greater angular stability, especially where curved is required, and so unwanted grating effects are avoided. A convoluted element with rejection band centred at 2 GHz cell area of 15 mm by ( $0.10\,\,\lambda \times 0.10\,\,\lambda$ ) has been deve...

A dual-frequency Q-/K-band circularly polarized feed with electronic tracking capability was developed. Four circumferentially located, externally coupled, diode controlled, resonant cavities were used at the horn throat to produce phase-center lateral movement. When used to feed a 24-in-diam. offset paraboloidal reflector, an average beam squint from boresight of 10 percent of the 3-dB beamwid...

We study the electromagnetic coupling of the array of Gaussian and multi-moded horn antennas to the dual-reflector submillimeterwave telescope on the ESA PLANCK Surveyor designed for measuring the temperature anisotropies and polarization characteristics of the cosmic microwave background. In this paper, we present the results of our analysis concerning the measurement of polarization with tilt...

A series-push-pull Mach–Zehnder modulator is integrated with a sampled-grating distributed Bragg reflector laser on a dual-quantum-well integration platform. The device exhibited greater than 7.8-dB extinction at 40 Gb/s with a 2.5-V drive voltage across a wavelength range of 1541–1566 nm. Bit-error-rate measurements at 10 Gb/s showed error-free operation and negative chirp.

In this paper a dual band and high gain H-plane horn antenna implemented by substrate integrated waveguide (SIW) using a single layer thin substrate is introduced. The proposed antenna consists of five parts of rectangular waveguide with different width arranged in a staircase manner to allow mode combination of fundamental and higher propagating modes of the structure. By adjusting the length ...