Investigations on microstrip patch antennas with different slots and feeding points

Abstract

S21 is Ϫ2.64 dB. In the 5.8 GHz passband, S11 is Ϫ12.49 dB and S21 is Ϫ3.8 dB. Five transmission zeros are generated as shown in Figure 4(b). The insertion loss of the transmission zeros are Ϫ73.2 dB at 0.62 GHz, Ϫ37.38 dB at 2.15 GHz, Ϫ39.42 dB at 3.21 GHz, Ϫ16.48 dB at 4.97 GHz, and Ϫ27.21 dB at 7.13 GHz.The proposed TLTB-BPF is fabricated using two FR4 boards with 0.4 mm thickness of each board. The total thickness is 0.8 mm which is composed of copper layers on both the top and the bottom layers with the loss tangent of 0.0245. The input and output feed lines are placed on the top layer. Figures 5(a) and 5(b) show the substance photograph of the proposed TLTB-BPF. The etched area is 36.9 mm ϫ 11.5 mm.A vector network analyzer is used to measure the return loss and the insertion loss of the filter. S11 and S21 simulation and measurement results of the proposed TLTB-BPF are shown in Figures 6 and 7, respectively. As shown in Figure 7, the first resonant frequency is 1.75 GHz, the second one is 3.48 GHz, and the third one is 5.81 GHz. For 1.75 GHz, the measured S11 and S21 are Ϫ13.2 dB and Ϫ0.97 dB, respectively. For 3.48 GHz, the measured S11 and S21 are Ϫ17 dB and Ϫ2.8 dB, respectively. For 5.81 GHz, the measured S11 and S21 are Ϫ11.1 dB and Ϫ3.8 dB, respectively. The specifications of both simulation and measurement results of TLTB-BPF are listed in Table 1.Although the measured results show well agreement with the simulation ones, the slight difference between the simulated and measured results might be due to the losses from the connection between the board and the vector network analyzer or the tangent loss of the FR4 board. The problems of the insertion loss and the frequency shifting can be improved by more accuracy fabricated technology. Also, the substrate material can be selected with lower tangent loss to have a better performance. Concerning with the frequency shifting problem, the pattern size can be slightly modified to tune the desired passband frequency. Table 2 lists the performance of the proposed TLTB-BPF and other triband filters in the previous design. The size of the proposed TLTB-BPF is appeared to be smaller than most of other triband BPFs except that proposed in [7]. However, the triband BPF in [7] using combined quarter-wavelength SIRs was fabricated by the substrate material with high dielectric constant and less tangent loss. Table 2 shows that TLTB-BPF has the advantage of miniaturization. CONCLUSIONSA novel trilayer triband microstrip bandpass filter has been proposed to provide three passbands centered at 1.8 GHz GSM channel, 3.5 GHz WiMAX channel, and 5.8 GHz WLAN band. Using microstrip line (top layer), open loop structure (middle layer), and the ground (bottom layer) to implement three different passbands results in a compact topology. A good agreement between the simulation and the measurement results is obtained. All passbands perform low insertion loss as well as low return loss. The center frequency, bandwidth, return loss, and insertion loss can all be adjusted by changi...

Analysis of a Notch Loaded Miniaturized Multifrequency Microstrip Patch Antenna

“…In recent days, microstrip patch antennas are highly utilized for applications in wireless communication due to its compact, planar, low cost, and light weight features. A number of design methods have been suggested by the researchers to increase the compactness of microstrip patch antenna [1][2][3][4][5][6][7][8][9][10][11][12]. Compact operation of air substrate patch antenna with more than 50% size reduction was reported by Wong et al [1].…”

“…A compact E shaped patch antenna with corrugated wings was proposed which results in 25% size reduction [5]. A maximum size reduction of 41% was reported by varying the dimension of slots and feeding point on microstrip patch [6]. Zhao et al [7] designed a compact patch antenna with 29.3% size reduction using split ring resonator embedded substrate.…”

Modified Π-Shaped Slot Loaded Multifrequency Microstrip Antenna

“…A planar fed microstrip antenna achieved size reduction of up to 40% by inserting slots of optimum dimensions into one of the radiating edges of the patch and parallel to the non-radiating edge [5]. A maximum antenna size reduction of 41% with multifrequency operation was achieved in [6] by varying the positions and dimensions of the rectangular slots on the patch. It was also reported by Singh et al [7] that by using cross slot on the rectangular and trapezoidal patch, the size of the antenna can be reduced by 34 and 41%, respectively.…”

CPW Microstrip Patch Antenna with Circular Slot for Wireless Applications

“…This poses design challenge for the microstrip antenna designer to meet the broadband requirements. Different methods [4] have been applied to overcome this problem such as using thick substrate with low dielectric constant, parasitic patch loading on the same layer with the main patch, stacked multilayer patches, U-slot and E-slot etched on the same patch and L-probe feeding.…”