In this article, we present a dielectric leaky-wave antenna with periodic metallic patches. Its design is made using HFSS software. Analysis of the antennas radiation pattern shows that one can control the direction of the main beam and the levels of minors lobes from the diameters and numbers of the holes. This significantly reduces the weight of the antenna while improving its performance.

In this paper, we determine the different possible couplings at the discontinuities of the two circular and rectangular waveguides using the trapez-method. The development of the normal modes of the fields allows us to obtain the amplitude of the fields of the transverse electric (TE) and magnetic (TM) modes. The calculation of the coupling integrals allows us to obtain the coupling matrices and to verify if the coupling is possible or not between the modes of these two waveguides.

The effect of a defected ground plane made up of photonic band-gap structure of circular slots or patches of the radii r on the bandwidth of a parallel line-coupled bandpass filter, realized on a dielectric substrate and of 3.3 GHz center, frequency is highlighted in this study. The use of defected ground plane increases the filter bandwidth and allows its use on a broad-band frequency.