Design and Analysis of Self Triplexing Antenna using Quarter Mode and Eighth Mode Substrate Integrated Waveguide Cavities

this paper presents the design and analysis of selftriplexing antenna. The antenna uses a quarter-mode substrate-integrated waveguide (QMSIW) cavity with two eighth-mode substrate-integrated waveguides (EMSIW) to operate at three different frequencies. The radiation properties of the QMSIW antenna are studied first using a moderately lossy substrate with $\tan \delta=0.002$. The QMSIW antenna radiates at 4.76GHz with a gain of 4.13dBi. To obtain a self-triplexing antenna two EMSIW and one Q MSIW are formed by cutting $a V$-shaped slot in a half-mode substrate integrated waveguide (HMSIW). The proposed triplexing antenna radiates at three different frequencies f1 $=$ $3.97 \mathrm{GHz}, \mathrm{f} 2=4.32 \mathrm{GHz}$, and $\mathrm{f} 3=4.63 \mathrm{GHz}$. Less than a $-25 \mathrm{~dB}$ isolation exists between the ports. For every band, With more than 2.5dBi of gain, the recommended antenna is superior. It is possible to adjust the working bands of each antenna separately without interfering with the other two antennas’ ability to operate.