Jie- Huang

Design of Short Microstrip Leaky-Wave Antenna With Suppressed Back Lobe and Increased Frequency Scanning Region

We demonstrate a short (1.08lambdao) microstrip leaky-wave antenna (MLWA) with suppressed back lobes and doubled frequency scanning region. The configuration of the proposed LWA contains three parts: the conventional open structure MLWA, the added monopole connected to the end of the MLWA on a defected ground plane, and the Yagi-Uda-like elements fabricated along the monopole. Because of the open structure of the MLWA, the reflected power produces a large back lobe radiated backwardly. By using the method of the added monopole connected to the end of the antenna, the remainder power could radiate through the added monopole without reflecting at the end. In addition, the Yagi-Uda-like elements fabricated along the added monopole enlarge the frequency scanning region due to the Yagi-Uda antenna characteristic. Compare to the conventional MLWA, the back lobe of the proposed LWA is suppressed about 8 dB at 5.0 GHz. The frequency scanning region of the H-plane (YZ-plane) of the proposed LWA can scan from 34deg to 57deg (total 23deg) while the frequency is operated from 4.6 GHz to 5.0 GHz; meanwhile the conventional MLWA scans from 30deg to 41deg (only 11deg) at the same frequency region.

A 24/60GHz dual-band millimeter-wave on-chip monopole antenna fabricated with a 0.13-μm CMOS technology

A 24 / 60GHz dual-band millimeter-wave on-chip antenna fabricated in TSMC 0.13-μm CMOS process is presented here. We design the feeding network by using the coplanar waveguide (CPW) structure. For the dual-band design, there are two major current paths to radiate. To avoid the harmonic frequency band of the low frequency-band, we add two strips to couple the harmonic frequency of the low frequency-band. Besides, the two strips let the higher frequency-band performance better. At this work, the simulator is based 3-D full-wave EM solver, Ansoft HFSS. The on-chip antenna size is 0.76 X 1.045 mm2. The bandwidth of the lower band and higher is about 180MHz and 700MHz, respectively. The simulated gain is about −9dB for 24GHz and about 1dB for 60GHz

Dual - Band MIMO Antenna with High Isolation Application by Using Neutralizing Line

In this letter, a dual-band Multiple Input Multiple Output (MIMO) antenna system with high isolation is presented. This design consists of two dual-band monopole antennas and neutralizing transmission line. For each antenna element, the operating frequency band covers from 2.4 GHz to 2.6 GHz and 5.2 GHz to 6 GHz. To improve the isolation between these two antenna elements spacing only 0.1225λ0 at 2.45 GHz, a neutralization decoupling transmission line is introduced. The measured return loss results of these two antennas are better than 10-dB in operating frequency band. The measured isolation between the two antennas is better than 15 dB. The envelope correlation coefficient (ECC) is smaller than 0.01 of whole operating frequency band. The peak gain of this design is better than 2 dBi in operating bands. This configuration can be applied for Wireless local area network (WLAN), WiMAX and Bluetooth communication system.

A triple-band circularly-polarized antenna with tuning fork shape strips

A new design of triple-band circular polarized antenna is presented. The proposed antenna is achieved using microstrip-fed with one L shape strip line, two circular strips and two circular patches. One circular strip radiates lower band, the other one covers higher band. By adding the circular patches and L shape microstrip the axial-ratio of this proposed antenna has been improved. This antenna operates in three bands which are 2.5GHz, 3.5GHz and 5.2GHz. These three operating bands can be applied for the WiMax and WLAN application. Experimental results show the proposed antenna has good return loss and circular polarization characteristics. The 10dB return loss impedance bandwidths for the band 2.5GHz, band 3.5GHz and 5.2GHz are 33%, 25% and 9.79%, respectively. The 3dB axial-ratio bandwidth are 11.4%, 6.2% and 11.8% with respect to 2.5GHz, 3.5GHz and 5.2GHz, respectively.

A novel short leaky-wave antenna for suppressing the back lobes

A method to suppress the back lobes of a short leaky-wave antenna by two designed considerations is present in this paper. The right triangular end of the LWA is used to reduce the power reflected backwardly and the linked rectangular is guided the remainder power to the ground. With a short LWA length, the back lobes are suppressed successfully both in simulated and measured results at 4.6 and 4.7 GHz. The differences of the gains between the back lobes and main beams are 13.1 dBi and 7.2 dBi at 4.6 and 4.7 GHz, relatively in the measurements. In contrast to the conventional LWA, the proposed short LWA would rather be useful in scanning systems.

Side Lobe Suppression of a Short Leaky-Wave Antenna by Phase Constant Tapering: Analysis and Design

Uniform leaky-wave antennas (LWAs) with limited length have suffered from the presence of high-level side lobes, which could lead to the reception of unwanted noise especially when the LWA is short. This communication examines how the phase constant of a short LWA can be manipulated to achieve side lobe suppression. The tapering of the phase constant is shown to result in higher order “image patterns,” which can be used advantageously for side lobe suppression. Validation of this principle is given by a cosine-shaped width-tapering profile design of a half-mode substrate-integrated waveguide (HMSIW) LWA. The measured results show that the side lobe level (SLL) of a short (1.4 λ0) HMSIW LWA has been suppressed to below -16 dB in the entire space wave leakage region using this tapering profile.

Novel Short Tapered Leaky Wave Antennas with Complementary Split Ring Resonantor for Back Lobe Suppression

Two novel short tapered leaky wave antenna (LWA) designs with a complementary split ring resonator (CSRR) structure are proposed in this paper. The CSRR structure is positioned at 1=4‚g away from the open-end edge of the LWA. For one of the antenna designs, the CSRR is placed at the ground plane; for the other one, the CSRR is placed on the antenna plane. The re∞ected wave caused by the open-end edge of the LWA is cancelled by the re∞ected wave caused by the CSRR, thus, the back lobe can be efiectively suppressed. The length of these two short tapered LWAs with CSRR design is only 1:2‚g at 4.3GHz. According to the measurement results, the impedance bandwidth is 650MHz for 7dB return loss, which covers the range from 4.3GHz to 4.95GHz. The back lobe can be suppressed efiectively about more than 12dB at the whole operating frequency band. The scanning range of the main beam is about 34 - , which cover the scanning angle from 10 - to 44 - .

A Dual Beam Scanning Microstrip Antenna

A dual-beam scanning microstrip antenna is proposed in this letter. The well-known characteristic of the conventional leaky wave antenna is the beam scanning with operating frequency variation. Here, two L-shaped slots are applied on the ground plane of the conventional leaky wave antenna structure to obtain the dual-beam scanning characteristic. The results show that this will work with relatively simple structure radiatng not only in the upper half-plane, but also in the lower half-plane. The upper half-plane main lobe scans from 356 - (i4 - ) to 24 - (scanning region is 28 - ). Meanwhile, the lower half-plane main lobe scans form 190 - (i170 - ) to 161 - (scanning region is 29 - ). The 7-dB return loss bandwidth is 600MHz from 3.4GHz to 4GHz. In addition, the measured average antenna gain is about 5.3dBi in the operating frequency.