Abstract: It is shown that replacing the sinusoidal chip in Golay complementary code pairs by special classes of waveforms that satisfy two conditions, symmetry/anti-symmetry and quazi-orthogonality in the convolution sense, renders the complementary codes immune to frequency selective fading and also allows for concatenating them in time using one frequency band/channel. This results in a zero...

A wide band, integrated linear printed antenna array with low sidelobe cosecant square-shaped beam pattern is presented. Array synthesis mainly about the wide shaped coverage, low ripple and sidelobe level (SLL) has been done using the modified least square method by matrix inversion. A printed dipole integrated with wideband balun has been chosen as the array element for wide bandwidth and goo...

The Butler matrix [1] is a beam-forming network for a multi-beam array antenna. The main-beam direction can be switched according to the input port. Conventional Butler matrix suffers from high crossover levels between adjacent main beams of -3.7dB and high sidelobe levels of -11.4dB independent on the number of ports, theoretically. In order to solve these problems, the configuration of a circ...

Reduced rank (RR) linearly constrained minimum variance (LCMV) adaptive beamforming with quadratic pattern constraints (QPC) is applied to space-time adaptive processing (STAP) for airborne radar. The problem is formulated for general rank reducing transformations and main beam and sidelobe pattern control is achieved by imposing a set of inequality constraints on the mean-square error between ...

In this paper, we design tapers for the periodogram in the case of nonuniformly sampled data. We consider both data independent and data dependent taper designs. In the data independent design case, we derive tapers by minimizing either the integrated sidelobe level or the peak sidelobe level of the spectral window. In the data dependent case, we extend the design by allowing the tapers to be c...

A new class of modular broadband low-sidelobe arrays, based on the theory of fractile (fractal tile) geometry, has been recently introduced. In this paper, the radiation properties of the Peano–Gosper fractile array are compared to those of the conventional square and hexagonal arrays. It is demonstrated that the Peano–Gosper array has the same desirable grating-lobe conditions as the hexagonal...

Contrast degradation is a critical problem in ultrasound plane wave imaging (PWI) resulting from signals leakage from the sidelobes. An ideal sidelobe reduction method may enhance the contrast without remarkably increasing computational load. To this end, we introduce a new singular value decomposition (SVD) sidelobe reduction beamformer for coherent plane wave compounding (CPWC) based on a pre...