Kyeongnam Jang

Design of a miniaturized UHF-band Zigbee antenna applicable to the M2M/IoT communication

In this paper, a miniature UHF-band Zigbee antenna is proposed. Considering a lighter weight and smaller footprint of the Zigbee platform attached to a walking person, the antenna is meandered on the top and partially short circuited on the bottom, and optimized with non-uniform widths and lengths of the radiating element, and capillary paths. Due to these contributing factors, the physical area is reduced by roughly 50% from the simple monopole antenna. Besides, the bandwidth of 20 MHz is obtained for the resonance frequency of 915 MHz, working appropriately for the UHF-band Zigbee application such as M2M and IoT. The full-wave simulation with the measurement verifies the proposed design.

Compact Dual-Band Three-Way Metamaterial Power-Divider with a Hybrid CRLH Phase-Shift Line

A compact dual-band three-way metamaterial power divider is proposed that has three in-phase outputs. Fully printed composite rightand left-handed (CRLH) unequal and equal power dividers are first implemented for 900-MHz and 2.4-GHz bands with the power-division ratios of 2:1 and 1:1, respectively. An initial 1:1:1 power divider is then achieved by incorporating the input of the two-way equal block into an output of the unequal block, and trimming the interconnection parameters. The condition of an identical phase at the three outputs of the power divider is then met by devising a hybrid CRLH phase-shift line to compensate for the different phase errors at the two frequencies. This scheme is confirmed by predicting the performance of the power divider with circuit analysis and full-wave simulation and measuring the fabricated prototype. They results show agreement; the in-phase outputs as well as the desirable power-division are accomplished and outdo the conventional techniques.

A low-profile dual-band SIW slot-array antenna based on LH material waveguides for a satellite communication receiver

Summary form given only. In this paper, a flat and small-footprint slot array antenna is proposed to build a light-weight X- and Ku-band satellite communication receiver. The overall geometry does not necessitate classic metallic waveguides to avoid being bulky and heavy, but has a very compact and low-loss duplexer flanked by the X- and Ku-band slot-array antennas all of which are in the form of SIW(substrate integrated waveguide). Taking it for granted that the SIW technique along with the slot-array design for high directivity in aerospace and defense industries has been around quite some time, there will be a question on the contributing factor of the proposed method. The conventional technology has not shown the case that SIWs and slot-arrays have been incorporated to a low-profile and new concept duplexer. Usually, a metal waveguide duplexer with a considerably large physical volume is located right in front of antennas and they are connected through an external cable or waveguide transition. This prohibits the printing-style system integration of the individual components. Manual cabling can cause degradation in the overall performance due to loss and mechanical error. In order to conduct easy manufacturing in one frame and achieve effective volume-reduction, all the components for the dual-band slot-array system are designed as the metamaterial SIW duplexer cascaded by the SIW X-band slot array and the Ku-band antenna. The proposed geometry is presented as follows with X-band and Ku-band far-field directive radiation patterns.

Reducing the Interference in Compact MIMO Antennas of CRLH-TL-Based Broadside-Capacitive and Slot Couplings

We significantly diminish the interference between the radiating elements for a miniature MIMO antenna system on the basis of composite right- and left-handed transmissionline(CRLH-TL). The element radiating structure has capacitively coupled parallel metal parts and slotted ground that correspond to the CRLH-TL to prohibit the volume from growing for an LTE high band. The metal line suspended over the radiating elements is optimally designed to drop the unwanted mutual coupling to -23 dB, as the entire MIMO antenna structure is small and it performs electrically useful. The test case is done for 2.5 GHz.

CRLH Leaky-wave beam-forming antenna with enhanced gain for the V2X communication

In this paper, a CRLH Leaky-wave two-dimensional array antenna for hemispherical beam-forming aimed at V2X communication is proposed. This antenna is composed of 4×4 feed-network and 4 rows of CRLH leaky-wave radiating structures that adopt the capacitive inter-element coupled mushrooms. Every single capacitive coupling uses 0.75 pF. We will show beam-forming and enhanced gain performances.

Triple-band spiral antenna array fed by composite right- and left-handed power-divider for gain-enhancement as a flat structure

Summary form only given. Spiral antennas have been adopted a lot over the linear polarization counterparts, since the circular polarizations of their far-field patterns can improve the versatility of wireless communication in multiple-fading and multiple-reflection environment. Nonetheless, there are shortcomings from the conventional spiral antenna systems, which are poor channel selectivity and large physical volumes. Most of the spiral antennas take tapered-shaped metal patterns to have the wideband, since the basic winding of a uniform line to a circle of a growing radius reduces to a narrow-band. The footprint of the aforementioned antenna should be large for a higher gain. With this, because the balanced feed assures the desirable spiral antenna performance, the differential feed or vertical balun is connected to the input port of the antenna, which makes it accompany a cavity beneath the metal pattern. Especially, when the main radiator is above the bottom PEC of the cavity by the quarter-wavelength, the volume of the cavity-backed and balun-fed spiral antenna becomes improper for portable devices and attachment to a vehicle. In this paper, a novel flat spiral antenna array is proposed. It is featured by a triple-band for channel selectivity and gain enhancement as well as a low-profile. To increase the antenna gain, the unit spiral antenna should be expanded to an array. Before this, the array element should have three bands of 2.4 GHz, 4.8 GHz, and 7.2 GHz, not in the form of a bulky cavity-backed geometry, but a planar structure. If the footprint of this element antenna is not enlarged, it has about the gain of 3 dBi. If this is wanted to grow up to 7 dBi, an array is needed. Two elements of planar spiral antennas are needed, and they need to be fed by a powerdivider. Coming up with a planar triple-band spiral antenna is a challenge, but the design of the power-divider to handle the three bands is harder than anything else, considering the existing power-divider technology. A thought can be given that the operational band of a power-divider is wide enough to include the three bands. However, the conventional technique for a wide-band power-divider elongates the physical structure by cascading sections or smooth transition of the branches. To eliminate this problem, a short CRLH(composite rightand left-handed) powerdivider is suggested to be combined with flat spiral antennas for the triple-band array.

Design of a Metamaterial-Based Compact Dual-Band 3-way Power Divider for Lighter L-band Military Satellite Transceivers

This paper proposes a compact dual-band 3-way power divider that helps lowering the weight of a transceiver for the L-band or multi-purpose satellite communication. Instead of the multi stages or tapering which ends up with loss accumulation and size-growth, the non-linear dispersive phases from the metamaterial CRLH(composite right and left-handed) properties are obtained by the accurate formulation and implemented by the short transmission line segments. Firstly, the CRLH dual-band two-way unequal power divider and equal power divider are separately designed. And then, the input of the two-way equal power divider is plugged in the output port of the unequal one, and the entire geometry is slightly adjusted for the desirable performance. The circuit analysis and full-wave simulation are used to predict the frequency responses and validated by the measurement of the prototype. Besides, the size-reduction effect is addressed.