A novel DOA estimation algorithm using directional antennas in cylindrical conformal arrays

In this paper, multilayer feeding network for linear slot array antenna is studied. A substrate integrated waveguide (SIW) corporate-feed network for linear slot array antenna based on three layers is presented. This design has eight right-handed circularly polarized radiation elements, one power divider with SMA connector to SIW adapter structure and six SIW power divider by coupling slot method. The feed network and antenna structures has been designed at X-band frequency. The SMA to SIW power divider and SIW power divider by coupling slot has in-phase and out-of-phase feature, respectively. The proposed feeding method takes the advantages of miniaturization of structure compared with the corporate-feed network by T-junctions. Also, proposed network for feeding radiation elements, eliminated undesirable surface current of the coaxial connector transition, which reduction of these currents causes lower side-lobe level at the antenna radiation pattern. Dimensions of manufacture array structure are 132.8 * 23 * 2.4 mm3 and the substrate is Rogers RO4003c. This antenna has the capability to expand the number of elements and feed network for achieving higher gain. Due to the unidirectional radiation pattern, this antenna useful for monopulse radar and automotive radar applications.

SIW Corporate-Feed Network for Circular Polarization Slot Array Antenna

A new noniterative method for pattern synthesis of unequally spaced linear arrays

In this article, the efficient development of a new class of multilayer microstrip patch antenna (MPA) fed by a substrate integrated waveguide (SIW) for X-band applications is presented. It consists of performing the feed network in the SIW and the radiating structure in the microstrip technology. The proposed structure demonstrates that the best alternative to a costly, heavy, and bulky rectangular waveguide feeder is an SIW, which provides miniaturization, performance enhancements, cost reductions, and ease of integration with MPAs. The proposed patch array is composed of three stacked layers from top to bottom, including two SIW layers as a feeding network and one layer as the antenna layer. To verify the concept of the proposed antenna, a prototype of a 2 × 2 SIW patch array with a 39 × 41 mm2 physical aperture was fabricated and measured with an impedance bandwidth of 9.18% for $\left|{{S}_{11}}\right|{ and a radiation efficiency above 78% in the whole operating frequency bandwidth. The maximum measured gain of the proposed array at 10 GHz is 11.1 dB, which is equivalent to 57.7% of the aperture efficiency. The proposed array can be easily developed to be used in larger arrays, and it is a good candidate for generating a symmetrical unidirectional pattern with a low cross-polarization level.

An X-Band Substrate Integrated Waveguide Fed Patch Array Antenna: Overcoming low efficiency, narrow impedance bandwidth, and cross-polarization radiation challenges

A compact multi-layer substrate integrated waveguide (SIW) monopulse antenna array operating at X-band is proposed. The structure consists of four stacked layers, including one layer for the radiating 4 × 4 rectangular microstrip antenna elements and two SIW layers for the comparator network. The sum and difference modes provide orthogonal radiation patterns in the azimuth and elevation planes. The two SIW layers of the comparator network feature a compact multi-feed design while maintaining high isolation between the antenna ports. To validate the proposed antenna concept, silmulations and measuremets are carried out. The obtained resuts show good performnces, a -10-dB impedance bandwidth of 13.45 % (9.35-10.7 GHz) for the sum and difference ports, better than 30 dB isolation between the antenna ports, the difference radiation patterns better than -38 dB null-depth. The comparison between the simulated and measuremed results shows a good agreement.

Monopulse Antenna Array Based on Three-Modes With Orthogonal Radiation Beams

Most of Equally Spaced Linear Arrays (ESLA) do not provide desirable Side Lobe Levels (SLL) and thus are less preferable in applications requiring minor SLLs. This paper presents a new algorithm to reduce SLL without any significant penalty on Half Power Beamwidth (HPBW) of the linear arrays. A periodic function is defined, which is equal to the main lobe direction and is zero along other directions; the values of this periodic function is equal to values of the SLL in original array. The excitation coefficients of this periodic function are obtained using commonly methods of pattern synthesizing. By subtracting the original array factor from the periodic function, SLL of the final array is reduced. The numerical results show that by this method, the HPBW is approximately unchanged, while the final array provides the smaller First Null Beamwidth (FNBW) compared to that of the original array.

Development a New Algorithm to Reduce SLL of an Equally Spaced Linear Array

Compact bilayer substrate integrated waveguide leaky wave antenna with dumbbell-shaped slot based on the TE20 mode

This paper, considering the tilt effect, presents a hemispherical antenna structure modeled by an improved conformal antenna array with the maximum angular coverage of the elevation axis to increas...

Mehdi Sharifi

Papers

Development a New Algorithm to Reduce SLL of an Equally Spaced Linear Array

Compact bilayer substrate integrated waveguide leaky wave antenna with dumbbell-shaped slot based on the TE20 mode

Conformal antenna array radiation pattern synthesis by tilt correction to improve Direction-of-Arrival estimation accuracy

Near optimal conformal antenna array structure for direction‐of‐arrival estimation

Beam wander of electromagnetic partially coherent flat-topped beam propagating in turbulent atmosphere