Small Wideband Microstrip Patch Antennas

In this project, we offer the design of 3 small wideband microstrip patch antennas. In fact, Microstrip antennas possess the interesting qualities of low profile, light in weight and simple structure. Nevertheless, its bandwidth is restricted to a few % that isn’t adequate for the majority of wireless communication systems at present. A few bandwidth enhancement approaches are actually suggested like making use of thick foam substrate, cutting 1 or 2 U-slots on the patch, stacking one more patch over the original one and making use of shorting pins. For a few applications like indoor wireless communications, standard patch antennas are probably not appropriate due to the big size particularly when functioning at lower microwave frequency. For that reason, many methods are actually suggested in the literature to deal with this challenge. Probably the most efficient method is to apply a shorting wall. This technique can minimize the size of a half wavelength patch by half to a quarter wavelength patch. According to a mix of these approaches, 3 novel antenna designs are introduced in this project report. Initially, a folded patch with a shorting wall is analyzed. This antenna is made up of folded trapezoidal patch having a shorting wall along with a shorting pin. By offsetting the feeding probe from the midline of the patch, yet another resonance is found. Incorporating this method with a two-sectioned feeding probe and a 50% thicker profile, the impedance bandwidth is increased from 29% to 56% (SWR=2). To figure out the connection between the position of the coaxial feed and the bandwidth, an evaluation is also provided. For the two-sectioned feeding probe, a parametric review is going to be completed showing the way the thickened diameter of the probe aids in improvement of the bandwidth. Additionally, a folded shorted patch with 2 L-slots cut on the primary part is researched. This design adds the concept of half double U-slots patch in the folded shorted patch and the 2 L-slots plays a role in the 2 extra resonances on the SWR curve. In addition, the length in between the folded part and the key part must be raised for maximum performance however the height of the key part is maintained low. This technique can protect against the high input inductance attributable to the coaxial feed. Because of this, a very wide bandwidth of 99% (SWR=2) and average gain of 6.8dBi are attained. Ultimately, a double folding structure is presented on a folded shorted patch. One more folded part is provided at the inner part of the half U-slot which enable it to further boost the bandwidth to 5:1 or 133% (SWR=2). Concurrently, to assist the impedance matching, a wings-liked wall is employed in order to connect the folded part and the key part.

Video: Wideband & Miniaturization of Microstrip Antenna


Chapter 1 Introduction
1.1 Introduction
1.2 Survey of Previous Research
1.2.1 Basic Structure of a Microstrip Patch Antenna
1.2.2 Bandwidth Enhancement Techniques
1.2.3 Size Reduction Techniques
1.3 Objectives of the Study
1.4 Structure of the Thesis
Chapter 2 Design of a Wideband Folded Patch Antenna with an Offset Probe Feed
2.1 Introduction
2.2 Geometry of the Proposed Microstrip Patch Antenna
2.3 Parametric Study of Probe Feed Position
2.4 Parametric Study of Probe Feed Diameter
2.5 Parametric Study of Trapezoidal Upper Patch
2.6 Effect of the Shorting Pin
2.7 Simulation Results of Broadside Gain
2.8 Experimental Results
2.9 Discussions
Chapter 3 Design of a Wideband Folded Patch Antenna with Double L-slots
3.1 Introduction
3.2 Geometry of the Proposed Patch Antenna
3.3 Parametric Study of L-slot Dimensions
3.4 Parametric Study of Upper Patch Height
3.4.1 Simulated SWR Results with Infinite Dielectric
3.4.2 Measured SWR Results with Finite Dielectric
3.4.3 Problems Found with the Antenna Fabrication Method
3.5 Effect of the Shorting Pin
3.6 Simulation Results of Broadside Gain
3.7 Experimental Results
3.8 Discussions
Chapter 4 Design of a Wideband Folded Feed L-Slot Folded Patch Antenna
4.1 Introduction
4.2 Geometry of the Proposed Antenna
4.3 Comparison with the folded patch feed design
4.4 Parametric Study of Folded Feed L-Slot Structure
4.5 Parametric Study of the Wings-liked Structure
4.6 Simulation Results of Broadside Gain
4.7 Experimental Results of Using Large Ground Plane
4.8 Experimental Results of Using Small Ground Plane….

Source: City University of Hong Kong

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