Izabela Slomian

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.

Microstrip Antenna Array With Series Feeding Network Designed With the Use of Slot-Coupled Three-Way Power Divider

A novel concept of a series feeding network of a microstrip antenna array has been shown. The proposed feeding network utilizes a four-port slot coupler as a three-way power divider, which is composed of two microstrip lines appropriately coupled through a slot within a common ground plane. The proposed power divider is used for simultaneous power distribution between two consecutive linear subarrays and between two 4 × 1 linear arrays constituting a single 8 × 1 linear subarray, where equal-amplitude and out-of-phase signals are required. Such a solution allows for realization of antenna arrays, in which all linear subarrays designed with the use of the “through-element” series feeding technique are fed at their centers from single transmission lines. The theoretical analysis as well as measurement results of the 8 × 8 antenna array operating within 10.5-GHz frequency range are shown.

Scalable Multibeam Antenna Arrays Fed by Dual-Band Modified Butler Matrices

A concept of dual-band multibeam antenna arrays that allows for efficient utilization of a common aperture has been proposed. The presented antenna arrays allow for achieving N-independent beams pointing at N different directions at higher frequency and N-independent beams at lower frequency pointing at N/2 different directions and having two orthogonal polarizations. As feeding networks, novel modified Butler matrices (BMs) have been proposed in which directional couplers having different properties in two frequency ranges have been for the first time utilized. To confirm the theoretical analysis, a dual-band multibeam antenna array fed by a modified 4 × 4 BM has been developed operating in 2.4 and 5.2 GHz frequency ranges.

Circularly Polarized Switched-Beam Antenna Arrays With Reduced Sidelobe Level

A novel method of sidelobe level reduction in switched-beam antenna arrays fed by Butler matrices has been proposed. The presented method takes advantage of circularly polarized two-port antenna elements, hence the sidelobe level reduction is achieved with conceptually lossless feeding networks without increasing the number of radiating elements. The presented approach allows for realization of amplitude taper by combining an N ×N Butler matrix with N two-way power dividers. Theoretical analysis as well as simulation and measurement results of the manufactured prototype operating in 2.4-GHz frequency range have been presented.

Composite right/left-handed leaky-wave antenna with adjustable radiation bandwidth

Abstract A novel approach to the design of a 1-D CRLH leaky-wave antenna has been proposed in which the frequency range of beam scanning can be adjusted without the change of unit cell’s physical length. The presented antenna is based on a unit cell composed of series capacitor connected in cascade with four sections of transmission lines and two symmetrically located transmission-line stubs. The unique feature of such a unit cell is that the phase constant’s slope vs. frequency and the resulting scanning bandwidth can be adjusted by controlling the characteristic impedance and the electrical length of the open-ended transmission-line stubs while all other parameters are fixed. The theoretical investigation as well as experimental results of the developed antenna operating at 2.5 GHz are shown, proving the correctness of the described design technique.

Octave-band aperture-stakced microstrip antenna element for wideband antenna arrays

An octave-band aperture-stacked antenna element has been presented. The designed antenna element utilizes two stacked rectangular patches which are excited by aperture coupling with the use of dual-feeding technique along with appropriate matching network. The designed feeding network allows for achieving additional resonance at the lower frequency band, and therefore, the antenna element operates within one frequency octave with improved both flatness of directivity and radiation patterns comparing to the previously described design. The proposed approach has been verified by measurements of the designed antenna element operating in 1.75-3.5 GHz frequency range.

Wide-beam microstrip antenna for application in 24 GHz short-range Doppler sensors

A wide-beam microstrip antenna for applications in short-range Doppler sensors has been developed. Beam widening has been achieved with the use of appropriately fed three radiating patches. To ensure a proper signal distribution along the array, a center radiating element has been designed as an aperture coupled patch fed at its center thorough the slot. Moreover, the center patch serves as a two-way power divider allowing for feeding two outer patches with appropriate amplitudes and phases ensuring simultaneously central symmetry of the antenna which improves radiation pattern.

Leaky-wave antenna with modified metamaterial unit cell for narrowing beam steering bandwidth

A novel unit cell of a composite right/left-handed transmission line has been proposed for application in leaky-wave antennas. It is shown that by the application of an open stub one can freely adjust the radiation frequency range in the right-hand region, and therefore, scanning of the main beam in the desired frequency range can be obtained. The results of theoretical analysis of the unit cell have been shown and confirmed by electromagnetic calculation of the proposed structure.

Single-layer four-beam microstrip antenna array

A four-beam microstrip antenna designated for two-dimensional beam scanning which utilizes a single layer of laminate has been proposed. A beam-forming network of the proposed antenna is composed of four appropriately connected 3-dB/90° directional couplers. With the use of the proposed network it is feasible to integrate it in a single metallization layer with radiating elements, reducing both size of an antenna and cost of manufacturing. The proposed concept has been verified by experimental results of a multi-beam antenna operating at 2.4 GHz.

Planar composite right/left-handed leaky-wave antenna featuring dual beam

A novel single-layer leaky-wave antenna utilizing composite right/left-handed transmission-line sections has been proposed. The proposed antenna is a 1-D periodic structure composed of identical unit cells. Each unit cell is constituted by a quasi-distributed series capacitance and two open stubs at opposite sides of a unit cell. The unique feature of this antenna is that main beam is scanned in one of the principal cut-planes from back-fire through broadside to end-fire, whereas in the other principal cut-plane the main beam is scanned as well, having different scanning angles in left-handed and right-handed regions. The design, simulation and measurement results of a proposed antenna operating at approximately 5-5.6 GHz are presented showing interesting features of the antenna.