Formulation In Resonant Length Research Articles

Circularly polarized gap-coupled variations of square microstrip antennas employing U-slot for WLAN and bluetooth applications

ABSTRACT Circularly polarized gap-coupled variations of square microstrip antennas using U-slot are proposed in 2400 MHz frequency spectrum for WLAN and Bluetooth applications. Design with patches gap-coupled along the two coordinate axes provides the optimum results. It yields axial ratio bandwidth of 376 MHz (15.8%) with a maximum broadside gain of above 10 dBi. Design methodology based on the resonant length formulation is proposed that helps in designing similar antennas in other frequency bands. Measurements have been carried out to validate the simulated results that show close agreement.

Design of folded rectangular microstrip antenna on thinner substrate for wideband response

ABSTRACT Wideband microstrip antenna is realized by adding more than one resonant modes in the patch. In this paper, on electrically thinner substrate, design of modified shape rectangular microstrip antenna by employing folded rectangular patch is presented for linear polarized wideband response. Unlike the conventional rectangular patch, radiation pattern and resonance frequency at the second-order resonant mode are modified and along with the fundamental mode, yield wider bandwidth. On substrate of thickness 0.045λ0, folded patch design yields bandwidth of more than 20% along with the broadside radiation pattern and gain more than 8 dBi. Against the reported wideband designs, proposed design does not employ parasitic patches, resonant slot, modified ground plane structures, but on thinner substrate achieves the bandwidth of more than 20%. Resonant length formulation and subsequent design methodology are presented, which is useful in realizing similar folded antenna as per the specific frequency band. Simulated results have been experimentally verified, which shows close agreement.

Multi-Resonator Wideband Designs of Semi-Circular Microstrip Antennas

Multi-resonator wideband designs of Semi-Circular microstrip antennas using narrow annular sectoral patches are proposed. The parasitic patches utilize the empty space around the fed patch, thus do not increase the antenna size by a large amount. Amongst various proposed designs, the gap-coupled design of slot-cut semi-circular patches along with narrow sectoral patches yields maximum bandwidth of greater than 900 MHz (>60%) with a peak broadside gain of 7.7 dBi. Against equivalent CMSA, it offers a 20% increase in bandwidth with only a 14.3% increase in the patch area. A resonant length formulation and subsequent design methodology are presented that is useful for re-designing similar antennae in the given frequency range as per specific application.

Electromagnetically Coupled Circularly Polarized Modified Triangular Microstrip Antenna

ABSTRACT Modified design of triangular-shaped microstrip antenna is proposed for circular polarized response which yields an axial ratio bandwidth of 68 MHz (∼5%) in the L-band. Furthermore, its electromagnetically coupled stacked design is presented, which yields enhanced impedance and axial ratio bandwidth of more than 1100 (∼70%) and 90 MHz (>7%), respectively. A single and stacked antenna offers a broadside pattern with a peak gain of 9 dBi. As a part of the design procedure, resonant length formulation at patch modes is presented. This serves as a guideline in the re-designing of similar antenna in a given frequency spectrum. Theoretical results have been verified experimentally with a good agreement.

Analysis and design of broadband U-slot cut rectangular microstrip antennas

Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design U-slot cut antennas at any given frequency is not explained. In this paper, first an extensive analysis to study the broadband response in symmetrical and a new configuration of asymmetrical U-slot cut rectangular microstrip antennas is presented. The U-slot tunes higher-order orthogonal mode resonance frequency of the patch with respect to fundamental mode to realise wider bandwidth. Further formulation in resonant length at modified patch modes in symmetrical U-slot cut antenna is proposed. Frequencies calculated using these formulations show closer agreement with simulated and measured results. Using proposed formulations, a procedure to design U-slot cut antenna at different frequencies over 800–4000 MHz range which shows broadband response is explained. Thus, the proposed work gives an insight into the functioning of widely used U-slot cut antennas and the formulations will be helpful for designing at any given frequency.

Broadband slot cut shorted sectoral microstrip antennas

Slot cut variations of shorted sectoral microstrip antennas are proposed which yields bandwidth of more than 900 MHz (>75%). Formulation in resonant length at modified shorted patch modes is presented. Frequencies calculated using them show close agreement with simulated results. Using proposed formulations, procedure to design slot cut shorted sectoral antennas at different frequency is presented, which gives wideband response. Thus, proposed work gives guidelines to design shorted compact antennas at any given frequency.

Proximity Fed Broadband 1200 Sectoral Microstrip Antenna

Novel configuration of 1200 Sectoral Microstrip antenna is proposed. Compared with equivalent circular patch, 1200 Sectoral patch has higher resonance frequency for the fundamental mode and it gives bandwidth of 1200 MHz (~59%). Resonant length formulation at fundamental mode in 1200 Sectoral patch is proposed. Using the same, design of 1200 Sectoral patch at resonance frequency of 1000 MHz is presented which yields more than 575 MHz (~ 50%) of bandwidth. This bandwidth is more than that obtained in circular patch operating in the same frequency range. Proposed 1200 Sectoral patch gives broadside radiation pattern with peak co-polar gain of more than 9 dBi.

Analysis and design of broadband 90° sectoral microstrip antennas

ABSTRACTAnalysis and design of broadband 90° Sectoral microstrip antenna derived from 270° Sectoral patch is proposed. The formulation in resonant length at its fundamental mode and procedure to design 90° patch at different frequencies is presented. The proposed 90° patch yields higher bandwidth with better radiation pattern characteristics as compared to equivalent circular, 270° Sectoral, rectangular and their slot cut variations. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:927–932, 2016

Slot Cut Ultra Wide Band Antennas

The ultra wide band antennas are required in applications where larger bandwidth for the transmitting signal is needed. They cover wide bandwidth in the range from 500 MHz to the frequencies above 8000 MHz. In this paper, a review of various techniques to realize ultra wide band microstrip antennas (MSA) is presented. They are realized by using different techniques like basic planar monopole antenna and the variations of the same by using different shapes of radiating monopole antenna, like, bi-conical, Bowtie, etc. They are also realized by using modifying the feeding strip shape or by cutting the slot inside the patch. The ultra wide band (UWB) response has also been realized by using fractal shapes in the radiating monopole antenna. Towards the end of paper, the scope of future work is proposed, wherein the exact formulation of resonant length is needed for planar monopole antenna at its fundamental and higher order modes as well as the explanation for the ultra wide band response in terms of operating modes in slot cut and fractal geometries.

Analysis of Slot Cut Broadband and Dual-band Rectangular Microstrip Antennas

The broadband and dual-band rectangular microstrip antenna is realized by cutting pair of toothbrush-shaped or step slots along the non-radiating edges of the patch. The toothbrush-shaped slot is said to introduce TMd0 mode in between the TM10 and TM20 modes of the rectangular patch and realizes broadband response. In step slot cut configuration, the slot introduces a mode near the TM10 mode resonance frequency of the patch and realizes dual frequencies. In this paper, a detail analysis to study the effect of slots on the broadband and dual-band response in these rectangular microstrip antennas (RMSAs) is presented. It was observed that the slot does not introduce any mode but modifies the resonance frequency of higher order orthogonal mode and realizes broadband and dual-band response. The slot alters the direction of surface currents at higher order mode and gives similar radiation pattern characteristics over the broader bandwidth and at the dual frequencies. In broadband RMSA, a formulation of resonant length at modified TM02 mode is proposed. The frequency calculated using the same closely agrees with the simulated result.