Search

A new LTCC (low-temperature cofired ceramic) system containing Al2O3 platelets instead of conventional Al2O3 particles as a filler material was investigated. As the Al2O3 platelets were arranged parallel to the casting direction during tape casting and had preferred orientation in the green tape, the linear shrinkage of the green body took place mainly in the direction perpendicular to the platelet planes with just a little shrinkage in the horizontal without any external force during sintering. The intended anisotropic shrinkage of the new LTCC system made the constrained sintering of 10-mm-thick ceramic body possible, which decreased the sintering shrinkage tolerance in the x–y directions of the 10-mm-thick ceramic body from 0.5% to 0.05%. The new LTCC system showed equivalent electrical properties and remarkable physical properties in comparison with a conventional LTCC system.

In this paper, the authors present the noise suppression performance using a decoupling capacitor which is embedded in an LTCC substrate. To embed high value capacitors (>20nF), a high K (over 500) material which can be co-fired with low K LTCC was developed successfully. Thin high K sheets under 10μm were co-laminated between low K sheets, which form the power and ground planes. Due to the short distance from the IC power pin to the decoupling capacitor, the ESL (Equivalent Series Inductance) is much lower than with surface mounted type capacitors, and so, SSN (Simultaneous Switching Noise) can be reduced significantly. To verify the noise suppression performance, we designed and fabricated a digital module using 100MHz CPLD (Complex Programmable Logic Device) on top of the LTCC substrate in which a 25nF decoupling capacitor was embedded. By measurement, we can see that SSN of CPLD on LTCC was reduced by 80% compared with designs that use surface mounted type 100nF capacitors. This embedded decoupling capacitor in LTCC (LEDC) can be useful for digital SiP (System In Package) to enhance noise performance and to reduce its footprint.

In this paper, we present the results of coblation nasal septal swell body (NSB) reduction for the treatment of nasal obstruction in patients with abnormally thickened NSB. The study design was a retrospective clinical series conducted at a single tertiary medical center. Eight patients underwent coblation NSB reduction. Pre-operative and post-operative nasal functions were evaluated by acoustic rhinometry and subjective symptom scales. We also analyzed pre-operative CT scan images and nasal endoscopic findings. The mean maximal NSB width was 16.4 ± 2.2 mm on pre-operative coronal CT scan images. The mean visual analog scale score for nasal obstruction was decreased from preoperative 7.63 ± 0.99 points to 3.88 ± 0.92 points (postoperative 3 months), 4.16 ± 0.78 points (postoperative 6 months), and 4.63 ± 0.69 points (postoperative 1 year). Six out of the eight patients were satisfied with the clinical outcome at 1 year after the procedure. To the best of our knowledge, coblation NSB reduction has not yet been reported in the medical literature. Our results show that it can be an effective treatment modality for nasal valve narrowing in patients with abnormally thickened NSB.

Nasal chondromesenchymal hamartoma is an extremely rare neoplasm of the nasal and paranasal sinuses. We present the case of a 10-month-old boy with a huge nasal chondromesenchymal hamartoma that was complicated by sleep-disordered breathing. The mass was completely resected by image-guided endoscopic surgery and confirmed histopathologically as a chondromesenchymal hamartoma. In this report, we discuss the characteristics and treatment of this unusual tumor.

Objectives As dental implant-related paranasal sinusitis has different pathophysiology and clinical features from primarily rhinogenic paranasal sinusitis, the standard treatment protocol for dental implant-related paranasal sinusitis has not yet been established. The aim of this study was to analyze the clinical characteristics and treatment results of dental implant-related paranasal sinusitis. Material and methods We conducted a prospective single-center study of 19 patients who were treated for odontogenic sinusitis developing in relation to dental implant from September 2008 through May 2012. The age of the patients ranged from 33 to 78 years, with the mean age of 54.5 years. Foul odor and postnasal dripping were the two most common complaints. All patients underwent nasal endoscopic examination and paranasal sinus CT before treatment, and initial conservative treatment for 1 week. Patients unresponsive to medical treatment underwent endoscopic sinus surgery (ESS). All patients were classified into the conservative and surgical groups for analysis and followed up for 2 years after initial diagnosis. Results Four patients (21%) were successfully treated conservatively, while 15 patients (79%) underwent surgical treatment. One of these 15 patients required revision surgery. After 2 years, all patients were successfully treated, so there were no more clinical signs of recurrent sinusitis in any patients. The survival rate of implants was 100%. Compared to those of the conservative group, symptom duration, the Lund–MacKay CT score, status of the ostiomeatal unit (OMU), and the condition of the maxillary sinus floor were significantly more severe in the surgical group. Conclusion In our study, the majority of patients who once developed paranasal sinusitis associated with dental implants required surgical treatment. Findings of paranasal sinus CT may be important in determining treatment option.

Nasal chondromesenchymal hamartoma is an extremely rare neoplasm of the nasal and paranasal sinuses. We present the case of a 10-month-old boy with a huge nasal chondromesenchymal hamartoma that was complicated by sleep-disordered breathing. The mass was completely resected by image-guided endoscopic surgery and confirmed histopathologically as a chondromesenchymal hamartoma. In this report, we discuss the characteristics and treatment of this unusual tumor.

This paper presents embedded substrate integrated waveguide (SIW) BPF and microstrip line-to-embedded microstrip line transition based on LTCC for 60-GHz application. The embedded SIW BPF is placed in LTCC substrate for compact system and integrated passive and active device on the other layer. But embedded SIW BPF performance is changed by interconnection via and transition. In order to low-loss interconnection with embedded passive device, microstrip line-to-embedded microstrip line transition with compensation circuit using series and shut line is proposed and implemented. The insertion loss of fabricated transition with compensation circuit is approximately 1 dB and return loss is below 10 dB from 56 GHz to 69 GHz. The proposed embedded SIW BPF including transition with compensation circuit exhibits a total insertion loss 2 dB at 61.8 GHz and the return loss is better than 16.2 dB with a 3-dB fractional bandwidth of 11.7 % (7.23 GHz). The measured insertion loss is lower than those in previous works. The overall size of the fabricated filter is 8 mm × 2.7 mm× 0.3 mm.

In this paper, an ultra miniaturized transceiver module for Bluetooth applications using 3-D LTCC system-on-package technology is presented. The proposed compact LTCC Bluetooth module is monolithically implemented with 0.5 mm thickness substrate embedding all passive components such as bandpass filter, balun, matching circuit, resistor, RF choke and bypass capacitor in order to reduce the overall size of module. The whole size of module is as small as 4.3 × 4.1 × 1.2 mm, which is the smallest size in the Bluetooth modules. The fabricated Bluetooth module reveals a transmit power of over 1 dBm and a sensitivity of −83 dBm.

An RF power amplifier (PA) for IEEE 802.11g WLAN terminals is implemented with 33 GHz-f/sub T/, 0.8-/spl mu/m-SiGe bipolar technology. This paper demonstrates a linearizer consisting of a varactor diode and a base-emitter junction diode of a bias transistor. Intermodulation distortion (IMD) is suppressed by optimized impedance of the linearizer. The reactance of the varactor diode is minimized at low output power level to eliminate IMD3, and maximized near 1-dB compression point (P1dB). IMD3 is improved as much as 0.2/spl sim/6 dB up to 20 dBm output power. The IMD3 value is less than -34 dBc at 3 dB back-off from P1dB. The power amplifier exhibits P1dB of 24 dBm, with power-added efficiency (PAE) of 31%, and power gain of 17 dB under 3.3V power supply.