Pattern Reconfigurable Elements Research Articles

Grating lobe reduction of sparse array with pattern reconfigurable element by time-domain synthesis

Grating lobe reduction of sparse array with pattern reconfigurable element by time-domain synthesis

Lower sidelobe phased array based on pattern reconfigurable elements

Pattern reconfigurable phased-array antennas can implement the function of beam control and overcome the limited scanning angle of traditional phased-array antennas without affecting the performance and operating frequency. In this article, a linear 1 × 4 phased-array designed for wide-angle scanning is presented. The unit includes an improved C-type dipole antenna, an I-typed resonator, and a ground. With the help of PIN diodes, the direction of the current on the patch is changed so that the unit can operate in two modes. The designed array has the advantages of a simple bias network, wide-beam scanning coverage, high gain, and low-sidelobe levels. Measurement results show that 2.85–3.66 GHz continuous beam scanning has been achieved in the range of −58° to 58°. Meanwhile, gain of up to 11 dBi is obtained, as well as in very good agreement with simulation. The results also verify the reconfigurability of the pattern and the feasibility of the design.

A linear wide‐angle scanning phased array based on pattern reconfigurable elements

AbstractA wide‐angle scanning phased array based on pattern reconfigurable elements is proposed. There are seven metallic cylinders arranged on both sides of each unit separately to improve the isolation. The design of metallic cavities instead of a ground plate and cooperating with cylinders ingeniously solved the inconvenience of DC bias supply, significantly reducing the size of the antenna element and the entire system, and also the coupling between elements. The 3 dB beamwidth of the joint pattern generated by the pattern reconfigurable technology covers 217° in H‐plane at 5GHz. The phased array can scan from −75° to 75° in H‐plane, with gain fluctuation within 1 dB. The phased array processes a high‐aperture efficiency of 75.76%. The measured results of the phased array prototype agree with the simulation.

Varactor-Loaded Pattern Reconfigurable Array for Wide-Angle Scanning With Low Gain Fluctuation

An improved phased array using pattern reconfigurable antenna elements in this communication is proposed to realize wide-angle scanning performance with low gain fluctuation. The pattern reconfigurable element is a microstrip Yagi antenna with its parasitic strips loaded with varactors. The reconfigurability of radiation pattern from the element is enabled by tuning the capacitive reactance of the varactors. Five elements were arranged in an equally spaced linear array, and the effects of several key parameter variations on the radiation characteristics of the array are provided. The proposed array is fabricated and experimentally verified. It is seen from the measured results that the main beam of the array can scan from -70° to 70° in the H-plane with a gain fluctuation less than 2 dB. Meanwhile, the coverage of 3-dB beamwidth of the array is from about -87° to 87°. The agreement between simulated and measured results validates our design exhibiting a good performance of wide-angle scanning.

Research on a Millimeter-Wave Phased Array With Wide-Angle Scanning Performance

In order to extend the scanning range of a phased array and maintain the scanning gain flatness, a novel millimeter-wave phased array with four linearly-arranged pattern reconfigurable elements is presented in this communication. The phased array has been designed, fabricated, measured and analyzed. The active patterns of each reconfigurable element are measured at different reconfigurable modes and the pattern scanning performance of the phased array is synthesized by using these active patterns. Furthermore, a genetic algorithm is used to lower the level of side lobes of the proposed phased array. The results show that the phased array can scan its main lobe from -75° to +75° in the elevation plane with a gain fluctuation less than 3 dB.

Beamsteering in Pattern Reconfigurable Arrays Using Directional Modulation

An array with pattern-reconfigurable elements is used to generate a digital modulation by switching the elements for every symbol. This technique is known as directional modulation. Because the modulation is generated at the antenna level, it gives control over the directions in which data is sent, unlike baseband modulation which transmits the same data in all directions at different power levels. A procedure for determining how to switch the elements to transmit only in a specified direction is outlined. Results indicate that compared to a traditional reconfigurable array, the directional modulation array allows information to be sent over a narrower beamwidth. Additionally, the method provides more selectivity in the possible transmit angles. Measured and calculated results from a four-element reconfigurable array are presented.

Exploration of Amplitude Tapering in Linear Phased Arrays with Pattern-Reconfigurable Elements

In classical periodic phased arrays, designers use the amplitude and phase of identical array elements to achieve desired characteristics such as sidelobe level, main beamwidth, scan angle, etc. A phased array composed of individual pattern-reconfigurable antenna elements possesses a third degree of freedom that may enhance or expand array performance. This work explores the functional benefits of utilizing radiation reconfigurable antennas with beam tilts in phased arrays, focusing on the effects of reconfigurability on sidelobe level, gain, and excitation dynamic range of amplitude tapered linear phased arrays. Simulated patterns from a broadside-to-tilted radiation reconfigurable antenna were used to calculate the overall array pattern via superposition for a linear, equally spaced array. Results indicate the concept has potential for lowering sidelobe levels, increasing system efficiency, and expanding array capability compared to that of a traditional planar array with fixed broadside elements.