Nobutaka Kidera

A V-band front-end with 3-D integrated cavity filters/duplexers and antenna in LTCC technologies

This paper presents a compact system-on-package-based front-end solution for 60-GHz-band wireless communication/sensor applications that consists of fully integrated three-dimensional (3-D) cavity filters/duplexers and antenna. The presented concept is applied to the design, fabrication, and testing of V-band (receiver (Rx): 59-61.5 GHz, transmitter (Tx): 61.5-64 GHz) transceiver front-end module using multilayer low-temperature co-fired ceramic technology. Vertically stacked 3-D low-loss cavity bandpass filters are developed for Rx and Tx channels to realize a fully integrated compact duplexer. Each filter exhibits excellent performance (Rx: IL<2.37 dB, 3-dB bandwidth (BW) /spl sim/3.5%, Tx: IL<2.39 dB, 3-dB BW /spl sim/3.33%). The fabrication tolerances contributing to the resonant frequency experimental downshift were investigated and taken into account in the simulations of the rest devices. The developed cavity filters are utilized to realize the compact duplexers by using microstrip T-junctions. This integrated duplexer shows Rx/Tx BW of 4.20% and 2.66% and insertion loss of 2.22 and 2.48 dB, respectively. The different experimental results of the duplexer compared to the individual filters above are attributed to the fabrication tolerance, especially on microstrip T-junctions. The measured channel-to-channel isolation is better than 35.2 dB across the Rx band (56-58.4 GHz) and better than 38.4 dB across the Tx band (59.3-60.9 GHz). The reported fully integrated Rx and Tx filters and the dual-polarized cross-shaped patch antenna functions demonstrate a novel 3-D deployment of embedded components equipped with an air cavity on the top. The excellent overall performance of the full integrated module is verified through the 10-dB BW of 2.4 GHz (/spl sim/4.18%) at 57.45 and 2.3 GHz (/spl sim/3.84%) at 59.85 GHz and the measured isolation better than 49 dB across the Rx band and better than 51.9 dB across the Tx band.

Fully Integrated Passive Front-End Solutions for a V-band LTCC Wireless System

A novel topology implementing a 3-D fully integrated filter and antenna function is proposed as a system-on-package (SOP) compact front-end solution for the low-temperature cofired ceramic (LTCC) based V-band modules. A 4-pole quasi-elliptic bandpass filter composed of four open loop resonators has been developed. It exhibits an insertion loss <3.5 dB, a return loss >15 dB over the pass band (~3.4 GHz) and a 3 dB bandwidth of about 5.46% (~3.4 GHz) at the center frequency of 62.3 GHz. In addition, a series fed 1 4 linear antenna array of four microstrip patches exhibiting high gain and fan-beam radiation pattern has been designed. Its 10 dB bandwidth is experimentally validated to be 55.4-66.8 GHz (~18.5%). The above proposed designs have been combined together, leading to the complete integration of passives with a high level of selectivity over the band of interest. The excellent overall performance of the integrated solution is verified through a 10-dB bandwidth of 4.8 GHz (59.2-64 GHz) and a return loss >10.5 dB over the passband.

Linear Tapered Cavity-Backed Slot Antenna for Millimeter-Wave LTCC Modules

In this letter, a linear tapered slot antenna (LTSA) which is backed by an air cavity is proposed and fabricated using low temperature cofired ceramic (LTCC) substrate. Traditionally, the high dielectric constant and the thick LTCC substrate seriously degrade the gain and radiation property performance because a large portion of the radiated fields are confined in the LTCC substrate. However, the proposed LTSA with the air cavity backing structure exhibits a high gain (4.9¿6.9 dBi) and a good end fire radiation pattern. Also, the proposed antenna has a wide impedance bandwidth (about 30 from 45 to 75 GHz). Through numerical and experimental analyzes, we found that the proposed antenna can be used for a variety of millimeter-wave applications, due to its broadband operating range and its easy integration with 3-D LTCC module.

Analysis and Application of 3-D LTCC Directional Filter Design for Multiband Millimeter-Wave Integrated Module

In this paper, we describe a systematic design and analysis procedure towards the successful implementation of 3-D low-temperature cofired ceramic (LTCC) multilayer loop directional filters at millimeter-wave frequencies. Directional filters represent a fundamental building block combining multiple filtering for mixing and multiplexing operations, hence reducing complexity while maintaining compactness. In this paper, different vertical coupling schemes are realized in order to implement the directional filters with the different performance optimums. The further use of the rectangular loop has been demonstrated as the optimum topology leading to the best performances. The filters have been measured to have less than 2.5-dB insertion loss in the bandpass path and higher than 25-dB rejection at 40 GHz, while occupying an area of 1.7times1.7 mm2. They demonstrate 4.7%-6.3% fractional bandwidth with better than 20-dB isolation. 40-GHz multiplexers for multiband applications with 4-GHz/8-GHz frequency separations have been designed and measured to have approximately 3-dB insertion loss in each band with better than 20-dB isolation between the outputs in passbands. This is the first complete report on LTCC directional filter-based designs towards the system-on-package (SOP) solution for the multiband millimeter-wave wireless modules

V-band Integrated Filter and Antenna for LTCC Front-End modules

In this paper, fully integrated filter and antenna functions are demonstrated as a system-on-package (SOP) compact front-end solution for the low-temperature cofired ceramic (LTCC) based V-band modules. The compact and easy-to-design integrated passive functions of filter and antenna have been hereby experimentally validated. A 4-pole quasi-elliptic band pass filter composed of four open loop resonators has been developed. It exhibits an insertion loss < 3.48 dB, a return loss > 15 dB over the pass band (~3.4 GHz) and a 3dB bandwidth of about 5.46 % (~3.4 GHz) at the center frequency of 62.3 GHz. In addition, a series fed 1by4 linear array antenna of four microstrip patches exhibiting high gain and fan-beam radiation pattern has been designed in a way that allows for an easy integration into a V-band multi-gigabit-per-second wireless link system. Its 10 dB bandwidth is experimentally validated to be 55.4-66.8 GHz (~18.5 %). The above proposed designs have been combined together, leading to the complete passive integration with high level of selectivity over the band of interest. The excellent overall performance of the integrated solution is verified through a 10 dB bandwidth of 4.8 GHz (59.2-64 GHz) and a return loss > 10.47 dB over the passband

60 GHz high-gain aperture-coupled microstrip antennas using soft-surface and stacked cavity on LTCC multilayer technology

In this paper, an aperture-coupled patch antenna integrated with a soft surface and the stacked cavity has been demonstrated on LTCC multilayer technology. A higher gain (~ 7.6 dBi) is achieved by stacking the cavity underneath the soft surface, which is 2.4 dB improvement compared to the patch antenna with the soft surface. It is also confirmed that the back radiation is significantly reduced by about 2.5 dB by stacking cavity to the patch antenna with the soft surface. The compact antenna with the soft surface and the stacked cavity can be easily integrated into 3-D 60 GHz modules and be easily extendable to array configuration for point-to-point applications in short-range indoor wireless personal area network (WPAN)

Use of a transparent conductive thin-film on a glass substrate in active integrated antenna arrays with double strong coupling

Active Integrated Antenna (AIA) arrays were fabricated on a glass substrate using a conductive thin film, which was thin enough to be transparent to realize a transparent RF component. It can be attached to a window glass keeping its visibility. This means a potential to develop to new applications in microwave communication. The AIA arrays, here, consist of CPW, double strong coupling and 2-element array. For the oscillation using the lossy transmission line, a backing conductor and a Partly Thickened Conductor (PTC) were used. It operated at 8.54 GHz with the in-phase mode and EIRP was 14.3 dBm.

A highly integrated 3D millimeter-wave filter using LTCC system-on-package (SOP) technology for V-band WLAN gigabit wireless systems

In this paper, the development of highly integrated three-dimensional (3D) filter solutions in multilayer low temperature cofired ceramic (LTCC) technologies is presented for millimeter-wave (mmW) compact, low-cost wireless front-end modules utilizing system-on-package (SOP) technology. These stacked-cavity embedded filters demonstrate an excellent performance (IL < 2.37 dB, 3-dB BW /spl sim/ 3.5 % at the center frequency of 57.3 GHz) and great potential for high level of 3D integration potential. The slot-coupled cavity filters have been realized by vertically stacking three identical cavity resonators employing rows of vias as sidewalls, thus representing a new class of devices that enable the 3D integration for V-band WLAN gigabit wireless systems.

A Compact Quasi-Elliptic Dual-Mode Cavity Filter Using LTCC Technology for V-band WLAN Gigabit Wireless Systems

In this paper, the development of highly integrated dual-mode filter solutions is presented for V-band compact, low-cost wireless front-end modules utilizing multilayer low temperature cofired ceramic (LTCC) technologies. A dual-mode cavity filter experimentally demonstrates a quasi-elliptic response and excellent performance in terms of low insertion loss ( < 2.76 dB) and high rejection. The rectangular shaped cavity resonator is first designed to generate two resonant modes (TE102 and TE201) that are orthogonal each other. Then, the location of the feeding structures and the size of the external slots are optimized to generate the quasi-elliptic dual-mode response. The filter has been implemented by employing rows of vias as sidewalls represent a new class of devices that enable the three dimensional (3D) integration for V-band WLAN gigabit wireless systems

Wideband, low loss and compact 3D LTCC balun with asymmetric structure for millimeter wave applications

A 3D LTCC (low temperature co-fired ceramic) millimeter wave balun using asymmetric structure was investigated in this paper. The proposed balun consists of embedded multilayer microstrip and CPS (coplanar strip) lines. It was designed at 40GHz. The measured insertion loss of the back-to-back balanced transition is -1.14dB, thus the estimated insertion loss of each device is -0.57dB including the CPS line loss. The 10dB return loss bandwidth of the unbalanced back-to-back transition covers the frequency range of 17.3/spl sim/46.6GHz (91.7%). The area occupied by this balun is 0.42 /spl times/ 0.066/spl lambda//sub 0/ (2.1 /spl times/ 0.33mm/sup 2/). The high performances have been achieved using the low loss and relatively high dielectric constant of LTCC (/spl epsiv//sub r/=5.4, tan/spl delta/=0.0015 at 35GHz) and a 3D stacked configuration. This balun can be used as a transition of microstrip-to-CPS and vice-versa and insures also an impedance transformation from 50 to 110 Ohm for an easy integration with a high input impedance antenna. This is the first reported 40 GHz wideband 3D LTCC balun using asymmetric structure to balance the output amplitude and phase difference.