Amit A. Deshmukh

Compact Broadband Slotted Rectangular Microstrip Antenna

The broadband and compact rectangular microstrip antenna (MSA) is realized either by cutting a half-U-slot or rectangular slot inside the patch. In this letter, broadband rectangular microstrip antenna, by cutting a half-U-slot and rectangular slot on the edges of the patch, is proposed. Due to the two resonant slots, the antenna gives more bandwidth as compared to only a rectangular-slot-cut or a half-U-slot-cut rectangular microstrip antenna. The proposed antenna has broadside radiation pattern over the entire bandwidth.

Analysis of Broadband Psi (Ψ)-Shaped Microstrip Antennas

A new Ψ -shaped microstrip antenna is reported, which increased the bandwidth of the E-shaped microstrip antenna by cutting an additional pair of slots on the other radiating edge of the E-shaped patch. The Ψ -shaped patch yielded a bandwidth of nearly 60% at a center frequency of around 5500 MHz. It gave a maximum gain of more than 10 dBi, which reduced to less than 4 dBi towards the higher frequencies of the bandwidth. In this paper, the broadband responses of the E-shaped and the reported Ψ -shaped patches are studied. In the E-shaped patch, the pair of rectangular slots did not introduce any mode, but modified the TM20 modes resonance frequency of the patch and, along with the fundamental TM01 mode, resulted in the broadband response. Furthermore, when an additional pair of slots were cut to realize the Ψ -shaped patch, they modified the higher-order TM21 modes resonance frequency of the patch. Along with the modified TM20 and TM01 modes, this yielded a larger bandwidth. Since the TM21 mode was present towards the higher frequencies of the bandwidth, the gain was reduced to less than 4 dBi. Furthermore, a proximity-fed design of a Ψ -shaped microstrip antenna in the same frequency band was proposed. The proposed configuration gave a higher bandwidth compared to the reported Ψ -shaped patch, with better gain characteristics over the bandwidth. A proximity-fed design of the Ψ -shaped patch in the 1000 MHz frequency band was also proposed. It gave a bandwidth of more than 50% with a broadside radiation pattern, and a gain of more than 8 dBi over the complete bandwidth.

Analysis of slot cut broadband and dual-band rectangular microstrip antennas

AbstractThe 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...

Broadband Proximity-Fed Modified Rectangular Microstrip Antennas

The bandwidth of a microstrip antenna is increased by using a thicker and lower-dielectric-constant substrate, or by using multi-resonator gap-coupled and stacked configurations, or by cutting a resonant slot inside the patch. However, with all of these methods, the bandwidth of the antenna is limited by the probes inductance for substrate thicknesses greater than 0.06λ0 to 0.07λ0. For substrate thicknesses larger than 0.07λ0, the bandwidth of the antenna can be increased by using a proximity-feeding method. In this paper, by using a combination of the proximity feeding technique and a thicker substrate, various broadband configurations of gap-coupled rectangular microstrip antennas, E-shaped and half-E-shaped microstrip antennas, and gap-coupled half-E-shaped microstrip antennas are proposed. All of these configurations give bandwidths in excess of 350 MHz (>;35% ), with gains of more than 7 dBi, in the 800 to 1200 MHz frequency band, with a broadside radiation pattern.

Multi-Band Configurations of Stub-Loaded Slotted Rectangular Microstrip Antennas

Triple-band rectangular microstrip antennas using combinations of an open-circuit nearly-quarter-wavelength stub, a resonant U-slot, and a pair of rectangular slots are proposed. A new configuration for a tour-band antenna has been realized by cutting two half U-slots inside a stub-loaded rectangular microstrip patch. The multi-port network models for these antennas are also proposed, which help in analyzing the mode distributions at various frequencies. The multi-band response has been experimentally verified, and close agreement was obtained among the simulated, measured, and theoretical results.

Analysis of Broadband Variations of U-slot cut Rectangular Microstrip Antennas

A very popularly used technique to realize broadband and compact microstrip antenna (MSA) is by cutting a slot at an appropriate position inside the patch. More frequently, U-slot and its variation, a half U-slot, have been used to increase the bandwidth (BW). In most of the available literature on U-slot cut antennas, a detailed explanation for broadband response due to U-slot has not been reported. In this paper, an extensive study for the broadband behavior for U-slot, half U-slot and double U-slot cut rectangular MSAs (RMSAs) is presented. The U-slot configurations with different aspect ratios (i.e., length-to-width ratio) for patch and slot dimensions have been studied. In U-slot and half U-slot cut patches, it has been observed that slot does not introduce any additional mode, but it modifies the fundamental and higher order mode resonance frequencies of the patch to yield broadband response. The slot also modifies surface current distribution at higher order mode to yield broadside radiation pattern characteristics over the complete BW, without any variations in the directions of principle planes. Further, in double U-slot cut RMSA, the second U-slot optimizes the impedance and frequency at modified higher order TM21 mode and, along with modified TM01 and TM20 modes, yields increase in the BW. This paper will give an insight into the functioning of U-slot cut antennas.

Formulation of Resonance Frequencies for Dual-Band Slotted Rectangular Microstrip Antennas

Dual-band and broadband rectangular microstrip antennas are realized by cutting U slots, V slots, or a pair of rectangular slots inside the patch. In these designs, depending upon where the slot is cut, the slot length is taken to be equal to either a quarter-wavelength or a half-wavelength in length. However, these simpler approximations of slot length as a function of frequency do not give a close match for different slot lengths and their positions inside the patch. In this paper, the surface currents and voltage distributions for a dual-band pair of rectangular slots, and for U-slot-cut rectangular microstrip antennas, are studied over a wide frequency range. It was observed that the slot does not introduce any mode, but reduces the higher-order orthogonal mode resonance frequency of the patch and, along with the fundamental mode, realizes the dual-band response. Furthermore, by studying the current and voltage distributions, a formulation for the slots resonant length on a glass epoxy substrate was proposed. The frequencies calculated using the proposed formulations agreed well with the simulated values, with an error of less than 5%. These formulations were also validated on RT-duroid substrate.

Broadband proximity fed modified E-shaped microstrip antenna

Commonly used technique to realize broadband microstrip antenna is by cutting the slots at an appropriate position inside the patch. The slot introduces a mode near the fundamental mode of the patch and yields broadband response. The bandwidth of an E-shaped microstrip antenna is further increased by cutting the pair of rectangular slots on one of its edge. This increase in bandwidth is due to another mode introduced by additional pair of slots. In this paper, modal variations, for this modified E-shaped antenna are studied. It has been observed that the slot affects the resonance frequency of higher order mode, which along with modes of E-shaped patch, realize higher bandwidth. Also the broadband proximity fed variation of modified E-shaped antenna in 950 MHz frequency range is proposed. This antenna gives a larger BW of 47% with broadside radiation pattern with a peak gain of approximately 10 dBi.

Broadband proximity-fed square-ring microstrip antennas

The fundamental and higher-order modes of a compact ring microstrip antenna are discussed. This provides insight into the functioning of this configuration. To increase its bandwidth and gain, various broadband proximity-fed configurations of a ring microstrip antenna in the 1000 MHz frequency band are proposed. A detailed explanation for the broadband behavior of all these configurations is presented. The proximity-fed square-ring antenna yielded a bandwidth of more than 250 MHz. A further increase in its bandwidth was realized by cutting a pair of rectangular slots on the edges of the ring patch. The pair of slots reduced the orthogonal TM02 modes resonance frequency of the patch and, along with the fundamental TM10 mode, yielded a bandwidth of more than 350 MHz. Furthermore, the proximity-fed gap-coupled configurations of rectangular-slot-cut C-shaped patches, which were derived from the ring patch, are proposed. These yielded a bandwidth of more than 500 MHz (>43%). Both of these slot-cut compact configurations gave broadside radiation patterns with gains of more than 6 dBi over the bandwidth. To further increase the gain and bandwidth of the slot-cut ring antenna, a multi-resonator configuration with parasitic ring patches, gap-coupled along the two coordinate axes, is proposed. This configuration yielded a bandwidth of more than 400 MHz with a peak gain of 9 dBi. In this configuration, a further increase in the bandwidth was realized by cutting a pair of rectangular slots on the edges of the ring patches that were gap-coupled along one of the coordinate axes. This configuration gave a bandwidth of more than 500 MHz with a peak gain of 9 dBi.

Analysis of shorted-plate compact and broadband microstrip antenna

A broadband configuration of a shorted-plate folded L-slot-cut folded-feed rectangular microstrip antenna was reported, which gave a bandwidth of 2840 MHz (133%). The broader bandwidth was obtained due to the coupling between various modes, which were either a half-wave or a quarter-wave in length. However, a clear description of the modes of the shorted patch that resulted in the broadband response was not given. In this paper, an analysis studying the broadband response of the reported configuration is presented. By studying the voltage and current distributions on the shorted patch, a formulation for its resonance frequency is proposed. The frequencies calculated using the proposed equation closely agreed with the simulated results. Furthermore, the broadband response of the reported configuration was analyzed by studying its resonance-curve plots and surface-current distribution. It was observed that the folded patch and a wing-like extension on the folded-patch portion, the L-slot, and the folded feed modified the various fundamental and higher-order mode resonance frequencies (such as f1/4,0, f1/4,1, etc.), as well as the impedances at these frequencies, to yield the broadband response. Furthermore, by optimizing the folded feed length, an increased bandwidth of 3504 MHz (139.2%) was obtained. Over the bandwidth, this configuration showed a radiation pattern with higher cross-polarization levels and with a gain of more than 5 dBi.