Dual-Band Circularly-Polarized Monopulse Antenna System With Single Layer Patches and Separated Feed Networks

Int J RF Microw Comput Aided Eng

2019

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Possibility of exploiting serial‐fed linear arrays for obtaining the direction of arrival (DOA) of frequency modulated continuous waveform (FMCW) sources is discussed in this article. The angle of incident wave is assumed to be in the range, [−90°, 90°], with ambiguity reduction compared with the previous work. At first, the serial‐fed arrays are assumed as a transmitter with triangular FMCW sources, composing modified frequency diverse arrays. An explicit angle dependency is obtained on the separations between the maximums of the produced spatial power pattern in a design procedure. The approach is generalized for modified sawtooth frequency modulated continuous waveform (SFMCW) sources, which are combinations of two SFMCW sources with two different slopes of frequency shifts. In addition, a measurement setup is implied assuming the serial‐fed array as the receiver and an antenna with a known FMCW source and an unknown DOA as the transmitter. The DOA will be obtained from the separations between maxima of the received signals. Advantages of the proposed structure are the simplicity of antenna structure, ability of operation with narrowband antenna elements, and ambiguity reduction compared with the previous work.

Section: Serial‐fed Fdas With Tfmcw Sourcementioning

confidence: 99%

“…Analysis of the serial-fed antennas is straightforward and the equations are indicated in Figure 1. 20,21 The normalized transmitted signal by the n-th element to a far-field range r n and angle θ at the time t is obtained by…”

Section: Serial-fed Fdas With Tfmcw Sourcementioning

confidence: 99%

Serial‐fed linear frequency diverse arrays for obtaining direction of arrival (DOA) of frequency modulated continuous waveform (FMCW) sources with ambiguity reduction

Int J RF Microw Comput Aided Eng

2019

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“…Serial feed has been used for arrays and for a circular patch antenna to produce circular polarization in Refs. . Yet, it has not been employed for printed multi‐fed helical antennas.…”

Section: Introductionmentioning

confidence: 99%

“…Yet, it has not been employed for printed multi‐fed helical antennas. The number of antenna arms is arbitrary since the serial feed can be designed for any feasible number of outputs . It brings about wide bandwidth with low‐level reflection coefficient for the multi‐fed helical antennas.…”

Section: Introductionmentioning

confidence: 99%

Design of wide‐beam triple‐fed helical antennas employing simple and efficient feed networks for bandwidth improvement

Micro & Optical Tech Letters

Hossein

Armaki

2018

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In this article, a simple method for designing feed networks for wide-beam multi-fed helical antennas, suitable for satellite communications, is studied. Power division with similar phase differences for these antennas is obtained using serial feed network. The number of antenna arms is arbitrary, since the serial feed can be designed for any feasible number of outputs. Triple-fed helical antenna is studied in this article, as an example. The proposed S band triple-fed antenna benefits from 3 dB AR bandwidth of 24%. It has also low-level reflection coefficients throughout the bandwidth. K E Y W O R D S circular polarization, helical antennas, multi-fed antennas, satellite antennas, serial feed AbstractIn this letter, a coupled line type of Wilkinson power divider (PD) composed of series transmission lines and coupled lines is proposed. By employing 2 pairs of transmission lines, the difference between the even-/odd-mode impedance of the utilized coupled line can be controlled; hence the performance of the bandwidth and out-of-band rejection can be changed simultaneously. Detailed design equations are derived and can be easily applied in future works. Due to the inherent bandpass characteristic of the

“…TE susceptance curve of the first layer should pass from the required curves on the desired frequency bands. The desired frequency bands are 1.9-2.3 GHz and 7.9-8.3 GHz [26,27]. Therefore we can increase the angle difference (beamwidth) from in [26] to more than by using the proposed RMCP.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Dual-Band Reflection-Mode Circular Polarizers Using Dual-Layer Rectangular Frequency Selective Surfaces

IEEE Trans. Antennas Propagat.

Armaki

2016

A new kind of dual-band reflection-mode circular polarizers (RMCPs) is introduced with wide bandwidth and wide-view at the operating frequencies. The proposed RMCPs are based on dual-layer rectangular patches on both sides of a substrate, separated by a foam or air layer from the ground plane. Required TE susceptance of the first layer patches to produce circular polarization is calculated using the equivalent transmission line model. Dimensions of the RMCP are obtained using parametrical study for the two frequency bands, 1.9-2.3 GHz and 7.9-8.3 GHz. In addition, it is indicated that the accepted view angle and bandwidth of the proposed dual-layer RMCP are improved compared with the single layer RMCP, significantly. Moreover, a tradeoff is observed for the dual-layer RMCP on the bandwidths of X band and S band that can be controlled by propagation angle of the incident wave. The proposed RMCP has 30.5 % and 33.7 % bandwidths for less than 3 dB axial ratio with incident angles and . Finally, simulation results are met by the measurement for three angles of the incident wave.