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We have constructed a series of new code families for the spectral-amplitude-coding optical code-division multiple-access (CDMA) system, and proposed new transmitter and receiver structures based on tunable chirped fiber Bragg gratings (FBGs). The proposed system has been analyzed by taking into account the effects of phase-induced intensity noise, shot noise, and thermal noise. We have also compared the performance of this system with that of a former system where a Hadamard code is used. It has been shown that the new code families can suppress the intensity noise effectively and improve the system performance significantly. When the effective power is large (i.e., 10 dBm), the intensity noise is the main factor that limits the system performance. When the effective power is not sufficiently large, thermal and shot noise sources become the main limiting factors and the effect of thermal noise is much larger than that of shot noise.

This paper proposes two novel designs of a multiband antenna using multiple rings. The first design consists of a set of self-similar circular rings. This is an alternative to the recently reported triangular fractal Sierpinski gasket monopole antenna, and comparison is made to this and the circular disk monopole antenna. The second design is realized by varying the shape of the circular structure to an elliptical one. Larger bandwidth and improved patterns are achieved. In comparison to the circular disk, improved radiation pattern control at higher operating bands, due to the discrete structure of the multiple rings, is shown by numerical and experimental results. The bandwidth is significantly larger than the Fractal Sierpinski gasket and Parany monopole.

A method has been proposed to simultaneously enhance the gain (14 dB), bandwidth (BW) (12.84% of the operating central frequency) and efficiency (94%) of a microstrip patch antenna. The antennas have been designed based on the patch size improvement technique to improve the fabrication tolerance. The designed prototypes have been fabricated by conventional low cost printed circuit board etching method and tested at X‐band (8–12 GHz) and 60 GHz band (57–66 GHz) frequencies. Antennas’ overall performance is maintained across their operating frequency range. The tested antennas for 60 GHz band convince the requirements for multi‐gigabits/s data rate wireless local area network and wireless personal area network applications recommended by IEEE 802.11ad and IEEE 802.15.3c standards. In all cases the simulation and the measured results are in good agreement.

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