A printed ultra‐wideband diversity monopole antenna

Abstract

However, in the case of the Class II network, the pairs of optimum Z mi and Z si values can be chosen according to the required bandwidth and desired stub impedance.To verify the electrical performances of the proposed structures, three independent phase shifters of 45°, 90°, and 180°, as shown in Figure 3, were fabricated using a teflon substrate ( r ϭ 2.17, H ϭ 0.508 mm, T ϭ 0.5 oz.). The impedance values of each phase shifter operating at 3 GHz were obtained from the design graph (see Fig. 2).The electrical performances for the input return and insertion loss, and the relative phase shift of each phase bit, were measured using a vector network analyser and are plotted in Figure 4 together with the simulation result for comparison.The measured performances in Figure 4 were in very close agreement with the theoretical predictions. All input return losses, including the SMA connector's characteristic, were more than 19 dB in the range 2.2-3.6 GHz. In general, as the phase shift increases, the operating bandwidth decreases. The results shown in Figure 4(b)-(d) show that the Class I network provides octave bandwidths at 90°phase shift, which is the same as that in [3], and also shows approximately 50% fractional bandwidth at 180°phase shift, which cannot be realized in [3]. CONCLUSIONA broadband phase shifter using a new switched network of two parallel double stubs has been presented. A theoretical analysis of the proposed structures has been performed, and a design graph has also been provided to find the optimum Z m and Z s values as a function of the desired phase shift. The Class I structure is appropriate for phase shifts of more than 90°and 180°, and the Class II structure is recommended for less than 90°-for example, 45°.

A Compact Band-Notched Ultra-Wideband Spatial Diversity Antenna

“…Many studies have been carried out to design UWB diversity antennas [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, the impedance bandwidth of the antennas in [5][6][7][8] cannot cover the whole UWB, and the sizes of the antennas are relatively large in [5,[9][10][11][12][13][14][15][16][17] which are not suitable for some portable devices' applications.…”

“…However, the impedance bandwidth of the antennas in [5][6][7][8] cannot cover the whole UWB, and the sizes of the antennas are relatively large in [5,[9][10][11][12][13][14][15][16][17] which are not suitable for some portable devices' applications. On the other hand, the frequency range for UWB systems between 3.1 to 10.6 GHz will cause interference to the existing wireless communication systems, such as the wireless local area network (WLAN) for IEEE 802.11a operating in 5.15-5.825 GHz, so the UWB diversity antenna with a band-notched function is desired in the design.…”

“…On the other hand, the frequency range for UWB systems between 3.1 to 10.6 GHz will cause interference to the existing wireless communication systems, such as the wireless local area network (WLAN) for IEEE 802.11a operating in 5.15-5.825 GHz, so the UWB diversity antenna with a band-notched function is desired in the design. However, the antennas in [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] do not have the band-notched function to avoid the interference. Recently, some antennas with band-notched function have been reported [22][23][24][25][26][27].…”

A Compact UWB and Bluetooth Slot Antenna for MIMO/Diversity Applications

“…The ECC can be calculated by using the measured S-parameters as explained in [9], and, for a two-port system, the ECC can be obtained from the S-parameters and (2). The ECC of the proposed antenna is below 0.01 across the whole operating frequency, as shown in Fig.…”

Printed Uwb Mimo Antenna With Different Polarizations and Band-Notch Characteristics

“…In recent years, the ultra wideband (UWB) antenna combining with multiple-input-multiple-output (MIMO) technology is becoming a hot point in wireless communication [1,2]. The antennas with a wide impedance bandwidth and good isolation performance are imminently required.…”