Design of an ultra wideband bandpass filter by using microstrip spur-line and ring shaped DGS with improved out of band response

Design of 5 GHz‐compact reconfigurable DGS‐bandpass filter using varactor‐diode device and coupling matrix technique

“…However, as shown in Figure 1, owing to the trade-off relationship between the power efficiency and the linearity of power amplifiers, it becomes difficult to obtain reasonable efficiency with the required linearity in the power amplifier [6][7][8]. Accordingly, various efficiency enhancement techniques for power amplifiers have been studied vigorously [9][10][11][12][13][14][15].…”

“…In particular, obtaining the high efficiency and linearity at the same time in a CMOS power amplifier is relatively very difficult compared to a power amplifier based on a compound semiconductor [10,11,15]. Although active devices in the CMOS process have been intensively developed in recent decades, the breakdown voltage of the CMOS active device has gradually degraded.…”

“…To reduce the size of the filters and improve the performance of the filter, researches have proposed various configurations. Compact and high performance filters have been developed by using DGS structures [9][10][11][12][13][14][15][16]. The DGS changes the current distribution on the ground plane which affects the characteristics of the transmission line such as its capacitance and inductance.…”