Series-fed Microstrip Antenna Array Research Articles

Feedline Design for a Series-Fed Binomial Microstrip Antenna Array With No Sidelobes

In this letter, a novel feedline configuration is proposed to eliminate the sidelobes by controlling the current distribution. This is achieved by adjusting the widths of the feedline of a series-fed microstrip antenna array. Even–odd mode analysis is provided to understand the effect of the feedline widths on current distribution. A binomial series-fed five-element microstrip antenna array is designed with the proposed feedline. The designed microstrip series-fed binomial array has no sidelobes in the radiation pattern with a realized gain of 11.1 dBi at the resonance frequency with 80% efficiency. It has a cross-polar level of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 40 dB and a front-to-back ratio of 20 dB. A prototype of the proposed design has been realized. The simulated and measured results are in good agreement.

A series-fed low sidelobe antenna for 24-GHz automotive radar

ABSTRACT In this paper, a series-fed microstrip antenna array with low sidelobe is presented for 24-GHz automotive radar. Chebyshev distribution is realized by different widths of a quarter-guided wavelength (λ g /4) feedline between adjacent antenna elements, achieving a low sidelobe level (SLL). A 1 × 8 antenna array is designed with the SLL of −23.1 dB at 24.125 GHz, which is extended to 2 × 8 and 8 × 8 planar arrays to improve array gain. The measured gain of 2 × 8 and 8 × 8 planar arrays is 17.3 dBi with an SLL of −23.6 dB and 22.1 dBi with an SLL of −24.7 dB at 24.125 GHz, respectively. In summary, the two antennas have excellent performance in the 24 GHz ISM band with the characteristics of good performance, simple structure, and easy integration, which can be applied to 24-GHz automotive radar.

A New Approach of Applying Chebyshev Distribution of Series Fed Microstrip Antenna Array for Radar Applications

In this paper, a new method of applying Chebyshev distribution for series-fed antenna array was proposed for radar applications. The first part of this study consists of applying the proposed method on antenna arrays working at 2.3 GHz (S-band radar applications) with 6, 8, 10, 14, and 28 elements, whereas the second part of the study is applying the method on antenna arrays working at 5.2 GHz (C-band radar applications) with the same number of elements. The achieved sidelob level is around (19.6- 24 dB).The obtained antenna gain is around (10-17.4 dB) depending on the number of elements. Whereas the horizontal half-power beamwidth is around (7◦ – 20◦).

W‐band low‐sidelobe series‐fed microstrip antenna array based on impedance matching section weighting method

A W-band low-sidelobe series-fed microstrip antenna array is proposed here. Impedance matching section weighting method is used in element series-fed weighting. This feeding method can effectively realise the desired amplitude distribution and sidelobe level of −30.1 dB is obtained in this design. The designed low-sidelobe antenna has great practical value in antenna of W-band portable radar.

Low-Cost Series-Fed Microstrip Antenna Arrays With Extremely Low Sidelobe Levels

This paper presents a new method of designing and implementing low-cost series-fed microstrip antenna arrays with low sidelobe levels by applying standard single-layer PCB technology. The method is based on the Z-parameter characteristics obtained from the electromagnetic full-wave simulation of the array elements by using a two-port network model. Two types of antenna arrays are designed and presented with the use of the proposed method. The first type is a uniform linear array with sidelobe level of 24.2 dB at the 24.125 GHz frequency band. The second type is a nonuniform linear array that provides at least 50% more physical space between the central patches to be used in 2-D arrays; this antenna has sidelobe level of 25 dB at 24.125 GHz. Both antennas achieve an excellent performance in the entire bandwidth of 250 MHz.

Design of horizontal airspace dividing radar antenna array

Antenna array has been widely used due to its advantages of high gain, low side lobe and narrow beam. For vehicle radar, antenna array is required to have narrow beam, wide measurement range, middle and long distance coverage in order for the high accuracy, wide angle range, middle and long distance of detection. Therefore, according to the Taylor polynomial microstrip antenna array theory, a 16-unit series-fed microstrip antenna array was designed in this study. Based on this and the beam forming technology, the 3-beam transmission antenna was designed to realize the division of airspace. Then the high frequency structure simulator and the optimization design module of the advanced design system are adopted for the frequency sweeping analysis, and the design size model data of antenna is optimized. The final experimental result shows that the design is qualified for the requirement of spatial division of narrow antenna beam.

Low-Sidelobe-Level Series-Fed Microstrip Antenna Array of Unequal Interelement Spacing

Using the differential evolution algorithm (DEA), low-sidelobe-level (SLL) series-fed microstrip antenna arrays of unequal interelement spacing (IES) are investigated. The proposed design method can achieve conversion between the SLL and half-power beamwidth (HPBW). The constraint conditions for the IES and amplitude are set up, and the element size is also taken into account in the pattern function. Based on the solutions from the DEA, two types of series-fed antenna arrays of unequal IES, i.e., uniform amplitude and nonuniform amplitude arrays, are designed, fabricated, and measured. Measurement results show that 8- and 10-element series-fed antenna arrays of unequal IES and nonuniform amplitude can achieve the SLL of $-\text{23.7}$ dB with HPBW of $\text{9.7}^\circ$ and the SLL of $-\text{25.3}$ dB with HPBW of $\text{8.3}^\circ$ , respectively. Compared to the traditional design methods, the proposed one can achieve the series-fed antenna array with a lower SLL and more narrow HPBW.

A Method for Analyzing a Linear Series-Fed Rectangular Microstrip Antenna Array

A novel method of analysis for a linear series-fed microstrip antenna array is developed, which is based on a set of canonical coefficients defined for the elements of the array. This method accounts for the mutual coupling between the elements, and allows for a design that has an arbitrary amplitude and phase of the radiating patch currents. This method has the simplicity of a CAD approach while maintaining an accuracy close to that of a full-wave method. The coefficients involved in the formulation are determined by full-wave simulation on either a single patch element or on two patch elements (for mutual coupling calculations).

Series-Fed Microstrip Antenna Lattice With Switched Polarization Utilizing Butler Matrix

A novel concept of a series-fed microstrip antenna array with switched polarization has been proposed. The presented antenna array consists of radiating elements connected together with transmission line sections, creating a lattice with series connections between elements. The lattice is also series fed using slots in the common ground plane. Moreover, it is shown that the proposed antenna array is capable of providing linear, dual-linear, circular, and dual-circular polarization when appropriately fed by a Butler matrix. The theoretical analysis and measurement results of a 4 × 4 microstrip antenna array operating within 5.5-GHz frequency range are presented, showing the potential usefulness of such a structure.

A Dual-Polarized Series-Fed Microstrip Antenna Array With Very High Polarization Purity for Weather Measurements

The design and analysis of a dual-polarization frequency scanning array antenna, operating in a frequency band of 2.7-3.0 GHz, for weather measurement applications are presented. Stacked patch elements are coupled to feed lines through slots etched on the ground plane. A wall of plated holes in the middle of the antenna column is designed to improve the isolation between the two input ports. Both simulation and measurements results confirm that very high polarization purity is achieved.

Series-Fed Microstrip Antenna Array With Inclined-Slot Couplers as Three-Way Power Dividers

A novel approach to the design of series-fed antenna arrays has been presented, in which a modified three-way slot power divider is applied. In the proposed coupler, the power division is adjusted by changing the slot inclination with respect to the transmission line, whereas coupled transmission lines are perpendicular. The proposed modification reduces electrical length of the feeding line to 1 λ, hence results in dissipation losses' reduction. The theoretical analysis and measurement results of the 2 × 8 microstrip antenna array operating within 10.5-GHz frequency range are shown in the letter, proving the novel inclined-slot power divider's capability to provide appropriate power distribution and its potential application in the large antenna arrays.

Series-Fed Microstrip Antenna Arrays and Their Application to Omni-Directional Antennas

The analysis of a series feed approach for N-element slot-coupled microstrip antenna arrays is presented. A cylindrical arrangement of six four-element arrays using this feeding mechanism is shown to achieve optimum omni-directional beam characteristics and exhibit pattern stability over frequency in the C-band. The cylindrical arrangement is measured to have a gain of 6 dB over 750 MHz of bandwidth. A closed-form omni-directional pattern analysis is also developed.

Fast iterative solution of integral equation with matrix decomposition algorithm and multilevel simple sparse method

In order to efficiently solve large dense complex linear systems arising from the electric field integral equations formulation of electromagnetic problems, matrix decomposition algorithm–singular value decomposition (MDA–SVD) is used to accelerate the matrix–vector product (MVP) operation. Based on the symmetry of the impedance matrix, a modified multilevel simple sparse method (M-MLSSM) is proposed. Combining MDA and M-MLSSM, the authors obtain a sparse representation of the impedance matrix and construct a fast MVP operation. A perfectly electrically conducting sphere and the series-fed microstrip antenna array are simulated to demonstrate the validity of the proposed method. Moreover, numerical experiments demonstrate that combined MDA and M-MLSSM can accelerate the MVP operation and reduce memory requirements by at least half an order of magnitude compared to MDA–SVD.

Wideband and Low Sidelobe Slot Antenna Fed by Series-Fed Printed Array

A combination of slots and series-fed patch antenna array is introduced leading to an array antenna with wide bandwidth, low sidelobe level (SLL), and high front-to-back ratio (F/B). Three structures are analyzed. The first, the reference structure, is the conventional series-fed microstrip antenna array that operates at 16.26 GHz with a bandwidth of 3%, SLL of -24 dB, and F/B of 23 dB. The second is similar to the reference structure, but a large slot that covers the patch array is removed from the ground plane. This results in a wide operating bandwidth of over 72% for , with a 3 dB gain bandwidth of over 15.9%. The SLL of this structure is improved to more than at 16.26 GHz, and stable SLL of over 15.5-16.4 GHz band is also exhibited. This structure has a bi-directional radiation pattern. To make the pattern uni-directional and increase the F/B, a third structure is analyzed. In this structure, rather than one single large slot, an array of slots is used and a reflector is placed above the series-fed patch array. This increases the F/B to 40 dB. The simulated and measured results are presented and discussed.

Theoretical and experimental study of feed network effects on the radiation pattern of series-fed microstrip antenna arrays

Microstrip series-fed arrays are often utilised for compact array designs. This type of feed structure minimises feedline lengths and feedline radiation. However, in practice, the radiation from the feed network still can be significant and it can have a noticeable effect on the array radiation pattern. Analysis is performed using the advantageous full-wave discrete image technique. Theoretical and experimental analysis of the radiation from a four-element series-fed microstrip array antenna, which fully includes the effect of the feed network, is presented. General conclusions are made for the purpose of practical designs.