Compact switchable filter with three state modes using simple microstrip structure

Abstract

This paper presents a compact multifunctional reconfigurable filter based on double coupled‐line structures with three different filtering modes. Three different working modes of the wideband bandpass filter (BPF), bandstop filter (BSF) and wideband filter with single notch can be switched. One prototype of the reconfigurable filter is constructed and measured. For the wideband BPF mode, the 3‐dB bandwidth is 84.5%with in‐band return loss (RL) higher than 21.5 dB and minimum insertion losses (IL) of 0.9 dB, and rejections for the upper stopband is higher than 22.5 dB. For the wideband filter with single notch mode, the 3‐dB bandwidth is 39.7% and 24.9%, with the minimum in‐band IL of 1.13 dB and 1.5 dB, respectively. The maximum rejections between the two bands are 32 dB, and the upper stop band rejections are higher than 19 dB. For the BSF mode, the 3‐dB bandwidth is 29.6%.

Novel FR4‐based low loss reconfigurable filter with four operating modes using movable transmission lines

“…Table 1 lists the comparison with other reconfigurable filters. Compared with the reconfigurable microstrip line filter using p-i-n diodes, [1][2][3] the proposed filter has much lower insertion loss. Compared with the reconfigurable SIW filter using liquid metal, 16 the proposed filter is easier to be fabricated with low cost.…”

“…[13][14][15][16][17] Reconfigurable technology using electronic components (such as p-i-n diode) is widely used in filter structures. [1][2][3] The electronic reconfigurable type has the advantages of fast speed and small volume. However, due to the introduction of electronic elements, several disadvantages co-exist at the same time, such as nonlinearity, low power capacity, and multiple parasitic parameters.…”

“…Bandpass filter plays an important role in wireless communication systems. There are many different technologies to implement bandpass filter, such as microstrip, [1][2][3] stripline, 4 substrate integrated waveguides (SIW), [5][6][7] metal rectangular waveguide, 8,9 substrate-integrated-suspended-line (SISL), [10][11][12] and so on. The reconfigurable technology in the bandpass filter is one of the key research contents.…”

“…Reconfigurable technology using electronic components (such as p‐i‐n diode) is widely used in filter structures 1–3 . The electronic reconfigurable type has the advantages of fast speed and small volume.…”