International Journal of Computer Applications (0975 - 8887) National Conference on Advances in Communication and Computing (NCACC 2015) Miniaturized Printed Filtering Antenna Deepika A. Agrawal Department of Electronics and Telecommunication Engg, R. C. Patel Institute of Technology, Shirpur, Dhule Jagadish B. Jadhav Department of Electronics and Telecommunication Engg, R. C. Patel Institute of Technology, Shirpur, Dhule ABSTRACT A new co-design approach is used to synthesize and design the new printed Bandpass Filtering Antenna. For the purpose of miniaturization and enhancing the overall performance of the circuit, a multi-function module is designed. It performs filter- ing and radiating, simultaneously with the help of co-design ap- proach. The parallel half wavelength coupled microstrip lines and inverted-L antenna is used for synthesizing the bandpass fil- tering antenna. The inverted-L antenna acts as a last resonator and provides load impedance of the bandpass filter. The equiv- alent circuit components of inverted-L antenna are acquired by comparing with the simulation results and then used for syn- thesis of Filtering Antenna. A complete design methodology is then described after the synthesis process. Here, third-order Chebyshev bandpass filter with center frequency 2.45 GHz and 0.1 equal-ripple response is designed as an example. The de- signed structure is compact and provides good design accuracy. General Terms Bandpass Filter, Antenna design Keywords Filtering Antenna, Filter Synthesis, Co-design approach, Inverted- L antenna. 1. INTRODUCTION Microwaves are the signals whose frequencies ranges from 300 MHz to 300 GHz, which implies the electrical wavelength from 1 m to 1 mm. Use of microwave energy for transmission purpose provides more bandwidth (which is critically important at present stage), miniaturization of system.. Microwave Power Transmission provides various advantages over the traditional system by facili- tating the interconnection on large scale [12]. Microwave signals are used for wireless communication systems, as they are not bent by upper layers of atmosphere. In wireless communication sys- tem, microwave filters holds great importance. Microwave filters are used to suppress the unwanted signals in stopband, and pro- vide transmission of wanted frequencies in passband. As the elec- tromagnetic spectrum is limited, frequencies should be shared and reused, which is done with the help of microwave filters. At present, the challenges and stringent requirements for microwave filters in communication system is raising high, which leads us to further developments in filter design technologies [12][14]. Microwave communication system is developing very rapidly, which corresponds to need of challenging highly efficient systems. In almost all wireless communication systems, antenna is a nec- essary component for receiving or transmitting microwave signals along with bandpass filters for suppressing unwanted signals. The impedance mismatch between the individually designed antenna and filter causes interference and thus affecting the performance of the circuit. Integration of two or more functions together leads to multi-function module miniaturizing the circuit size and lead- ing to improved circuit performance. Radiating and Filtering are the most important functions of the communication system, inte- grating these functions into a single module will reduce the addi- tional circuit and enhance the overall performance of the circuit. This module is Filtering Antenna, performing both the functions at the same time. Filtering Antenna provides shaping of frequency re- sponse [1],[11],[12]. Many efforts have been carried out in past for synthesis and de- signing of Filtering Antenna[3]-[8]. In [3], filtering function was integrated in an electromagnetic horn. The filtering function was developed by inserting discontinuities with the help of metal posts in an electromagnetic horn antenna. To achieve their aim of sep- arately specifying filtering and radiating functions, a mixed simu- lation electromagnetic-circuit was used. But standard method was not followed and also cross polarization was slightly detorioted. In [4], cavities were created in leaky waveguide so as to control the bandwidth and hence, develop the filtering function. Leaky waveg- uide area along with the cavities provided radiating and filtering functions simultaneously. Due to cavities, bandwidth of antenna is limited and also matching between the structures is improved. This design did not consider the filter?s or antenna?s specifica- tions. In [5], to control the bandwidth of antenna, the bandpass filter was directly inserted at the feed point of patch antenna. But they faced problems in mounting of two structures together along with less controlled bandwidth and low radiation efficiency. In [6], Co-design approach was used to enhance the performance parame- ters of the circuit. 3-pole compact CPS structure is used as an filter, while CPS fed loop is used as an antenna and both are designed by co-design approach. For combining these two structures, a high impedance transmission line is used which needs extra additional circuit area. Also the frequency response was not as per the expec- tations. In [7], multilayered (ceramic/foam) technology resulting in the composite structure made of high and low permittivity layers was used for the purpose of integrating filtering and radiating func- tions together. The foam layer facilitated the larger bandwidth and ceramic layer minimized the size and impedance level. But such a complicated design led to various design constraints. In [8], a sin- 25