Design of compact size and tunable band pass filter for WLAN applications

Abstract

Compact size and tunable band pass filter based on open-loop resonators is proposed. The proposed structure consists of dual-armed microstrip open-loop resonators. A second armed open-loop resonator, which acts as band rejection resonator, is connected directly to the input and output ports to achieve the desired band pass behaviour. The open-loop microstrip resonators are combined with four lumped capacitors to reduce the overall size of the proposed filter. The capacitors are inserted at places where maximum electric field is occurred in order to increase the effective capacitance and reduce the resonant frequency as well. The resonance frequency is translated from 6.75 to 5.3 GHz for WLAN applications. Consequently, the filter size will be more compact and the filter performance will be improved by enhancing the energy stored in the resonator. The proposed design using lumped capacitors represents a reduction in size of more than 35% when compared with conventional filter without using lumped capacitors. A good consistency is achieved between simulated and measured results.

Effects of dielectric substrates on piezoelectric transducer tunable filter

“…of no metalized via-hole grounding and of producing either an electrical or a magnetic coupling between two resonators. 1,14,15 Based on the theory of transmission lines, 16 an open loop resonator has a length of half a wavelength and at the middle of which the intensity of a current is the largest, and at both ends of which the intensities of voltages are the largest, so the coupling between back-to-back resonators is magnetical and the coupling between feedline and resonator is electrical, and the gap between two feedlines forms a capacitor. We easily obtain the structure of the proposed filter, as shown in Figure 4.…”

Design of Dual-Band Dual-Mode Band-Pass Filter Utilizing 0° Feed Structure and Lumped Capacitors for WLAN/WiMAX Applications

“…With the repaid developments of the wireless communication systems, designing filters with multi bands is preferable. More studies have been conducted to achieve the dual-band response of the band pass filter since there are a lot of applications that should be operated simultaneously without any interference such as WLAN, which runs at 2.45, 5.2, and 5.8 GHz and WiMAX, which also runs at 3.5 and 5.2 GHz [10][11][12]. Due to the distinct properties of multiband BPFs, such as wide rejection band, deep transmission zeros, high selectivity, sharp roll-off rate, and tunable behavior, they have a specific place in the RF receivers.…”

Design and optimization of a new compact 2.4 GHz-bandpass filter using DGS technique and U-shaped resonators for WLAN applications

“…To remedy this problem we will propose two more efficient methods that will have given us a compact size, the first method touches the shape of the line we will bend the line on itself in order to gain a little surface [12][13][14][15][16][17][18][19][20][21]. In the second method we will integrate slots (DGS) at ground level to decrease the dimensions of these lines and improve the performance of the filter [22][23][24][25][26].…”