A Novel Design Algorithm and Practical Realization of Rectangular Patch Antenna

8/3/2019 A Novel Design Algorithm and Practical Realization of Rectangular Patch Antenna

1/15

Progress In Electromagnetics Research M, Vol. 17, 1327, 2011

A NOVEL DESIGN ALGORITHM AND PRACTICALREALIZATION OF RECTANGULAR PATCH ANTENNALOADED WITH SNG METAMATERIAL

M. R. C. Mahdy, M. R. A. Zuboraj, A. A. N. Oviand M. A. Matin

Department of Electrical and Electronic EngineeringBangladesh University of Engineering and TechnologyDhaka, Bangladesh

AbstractIn this paper, for the very first time, a general algorithmfor designing rectangular microstrip patch antenna, partially loadedwith SNG (Single Negative) (MNG ( Negative) and ENG (Negative)) metamaterial has been proposed to achieve better radiationperformance. Then, applying our proposed algorithm, theoreticallywe have predicted novel dual band miniaturized rectangular patchantennas (loaded with MNG metamaterial) for two different bandsusing unconventional interface resonance mode under fundamentalTM010 mode. Then we have proposed a complete design of magneticinclusions, presenting full wave numerical simulations of the structure,which effectively supports the theoretical expected resonant modes aswell as satisfactory radiation pattern performance. Prior to our currentwork, impossibility of sub-wavelength or electrically small rectangular

patch antenna has been demonstrated using ENG metamaterial.However, in this paper, we have indicated a direction towards thereal-life implementation of possible miniaturized rectangular patchantennas partially loaded with MNG metamaterial. The algorithmproposed in this paper is the key to choose the appropriate materialparameter to design all such antennas.

Received 20 November 2010, Accepted 31 January 2011, Scheduled 7 February 2011

Corresponding author: Mahdy Rahman Chowdhury Mahdy ([email protected]).


2/15

14 Mahdy et al.

1. INTRODUCTION

Microstrip patch antennas, though popular for several applications, aredifficult to miniaturize, since their resonant frequency is determinedby the dominant modes of the patch cavity. Nevertheless, numerousminiaturization techniques using shorting posts, active loading orhigh permittivity dielectrics [1] have been conceived to lower theresonant frequency of patch antennas without increasing their size.Unfortunately, shorted posts, etched slots, and parasitic elements areoften empirical (based on a cut-and-try process), and the additionalparts will inevitably cause deformed radiation pattern and high crosspolarization as a side effect [2]. Moreover, dual frequency patch

antennas provide an alternative to large bandwidth planner antennas.In radar and communication system applications, patch antennas haveattracted much interest due to their light weight and low cost. A uniqueradiating structure is desirable to accomplish these operations [3].Probably, metamaterial based antennas can be the best solution forall these demands stated above. In [4] and [5] possibility of sub-wavelength patch using only circular patch has been demonstrated.But yet solution of reduced size rectangular patch antenna has notbeen reported in literature. In this contribution we have reported

partial solution with proper practical realization to reduce the size ofrectangular patch antenna applying our novel algorithm.At first, Engheta proposed a sub-wavelength cavity resonator

formed by a pair of conventional DPS (Double Positive) and DNG(Double Negative) materials with the DNG as a phase compensator [6].However, in the quasi static limit, when the retardation effects arenegligible due to the small dimensions of such components and onlyone of the two constitutive parameters interact with the field dependingon its polarization, even single negative (SNG) materials, i.e., ENG orMNG, may be utilized to achieve similar effects. Later, Alu et al. [4]

have proposed design method to obtain sub-wavelength rectangularpatch antennas using DPS-ENG bi-layer. But it has been shownthat such patches (rectangular), even if working at resonances in thesub-wavelength region, do not radiate energy efficiently in free space(broadside null radiation pattern; Figure 2 of [7]). It has been predictedthat these rectangular antennas partially loaded with metamaterial canonly be good resonators but may not be good radiators [4].

In this paper, at first (sec-2) we will give an algorithm for themodification of radiation pattern using MNG and ENG metamaterial.

Then applying the algorithm, we shall theoretically predict thenovel design of miniaturized rectangular microstrip patch antennaspartially loaded with MNG metamaterial for dual band applications.


3/15

Progress In Electromagnetics Research M, Vol. 17, 2011 15

Later, using spiral ring resonators we shall propose a completedesign of magnetic inclusions for real-life implementation of possible

miniaturized rectangular patch antennas partially loaded with MNGmetamaterial. So, the overall work has been demonstrated here alongwith our proposed novel algorithm, code based simulation and fromthe point of view of practical-life implementation.

2. PROPOSED ALGORITHM FOR DESIGNING

In Figure 1, the geometry of an un-slotted patch antenna withmetamaterial block is shown. It consists of a metallic patch with

transverse dimensions (LpWp) placed over a ground plane (distanceh). The underneath substrate (which is Lp Wp h in volume) isinhomogeneous, filled with two isotropic and homogeneous materialswith permittivity and permeability 1, 1 and 2, 2. The filling ratioof the DPS is (i.e., the length of DPS block under the patch is L).The problem is proper choice of necessary parameters to design suchan antenna to get not only interface resonance but also good radiationpattern. To solve these problems, in this section, we have proposedan algorithm (with the help of some of our novel approximations)for a rectangular Microstrip patch antenna partially loaded with

Figure 1. Geometry of a rectangular microstrip patch antennapartially loaded with metamaterial (ENG, MNG or DNG). fp =feed position from DPS and metamaterials interface. fr = chosenresonant frequency. Detailed information and constitutive parametersare: 1r = 1. Case 1: Lp = 50mm, Wp = 40mm, Lg = 75mm,Wg = 75mm, fp = 21.4356 mm, h = 5mm, = 0.8176, 1r = 3.8,1r = 1 and 2r = 5.1, 2r (at fr) = 0.1091 in case of MNG loading.

Case 2: Lp = 30mm, Wp = 24mm, Lg = 50 mm, Wg = 50mm, fp =10.647 mm, h = 3mm, = 0.7439, 1r = 4.4, 2r (atfr) = 0.1091and 2r = 4.4 in case of MNG loading.


4/15

16 Mahdy et al.

PROPOSED ALGORITHM FOR DESIGNING

RECTANGULAR PATCH ANTENNA

LOADED WITH SNG METAMTERIAL

Input Parameters:

should be chosen according to k L

range1

Step-4

Evaluate electric field4

at the two

radiating edges using a single solution

Step-1

Choose range of 2 (m points), (npoints) and declaredispersive relation

as a function f

Step-2

Evaluate dispersive function using

(mxn times: loop)

Step-3

Check solutions of dispersive function

f( 2, ) using specified precision3. If it

satisfies equaiity f( ) 0, then go

to step-4. Otherwise return to step-1.

Output

Final output of valid values

Step-5

Check valid field conditions5 at the

radiating edges. If it satisfies conditions

go to next step. Otherwise return to

step-4 and check other solutions of

FOR MNG METAMATERIAL LOADING

1. Range for MNG metamaterial loading:

135

A Novel Design Algorithm and Practical Realization of Rectangular Patch Antenna

Documents

Transcript of A Novel Design Algorithm and Practical Realization of Rectangular Patch Antenna