Seong J. Cheon

3- to 5-GHz Ultra-Compact Bandpass Filter With Independent Transmission Zeros Using PCB Embedding Passive Technology

A compact ultra-wideband bandpass filter was newly designed and implemented by embedding all the passive components into a printed circuit board with a high dielectric composite film layer. It was designed using a modified third-order Chebyshev circuit topology to obtain a large bandwidth. J-inverter transformation technology was then applied in order to reduce the size of the filter and avoid unwanted electromagnetic coupling among the filter circuit elements. A capacitor and two inductors connected in series with three parallel resonators were newly applied to generate three independent transmission zeros for improving the rejection characteristics at the lower and upper stopbands of the proposed filter. The measured maximum insertion loss in the passband range from 3.1 to 4.75 GHz was better than 1.68 dB and the return loss was higher than 12 dB. The transmission zeros of the measured response occurred at 2.2 and 5.15 GHz and provided suppressions of 31 and 20 dB in the wireless local area networks bands of 2.4 and 5.15 GHz, respectively. The group delay in the passband was lower than 0.62 ns. The size of the fabricated filter was 2.9 × 2.8 × 0.55 (H) mm3.

High-Level Embedded Passive Triplexer and Quintplexer Module into Organic Packaging Substrate

In this paper, fully embedded passive triplexer and quintplexer module into organic packaging substrate were presented for US CDMA handset applications. First, the passive triplexer was implemented by embedding all passive elements and circuits into multi-layered FR-4 packaging substrate and surface mounting GPS surface acoustic-wave (SAW) band pass filter on top of the organic packaging substrate. The passive triplexer circuit with 8 passive elements was comprised of a diplexer, parallel resonator, and matching network. The CDMA quintplexer module was fabricated by assembling the triplexer with DCN and PCS duplexers on FR-4 evaluation board. The sizes of the triplexer and quintplexer module were approximately 3 mm times 4 mm and 7 mm times 6 mm, respectively. These fabricated devices exhibited good performance characteristics, small size/volume, low cost, and high-level integrity onto a multi-layered organic packaging substrate. The simulated performance characteristics were agreed with the simulated ones.

Compact quintplexer module with meshed ground plane for US-CDMA handset applications

Compact quintplexer module with PCB embedded passive triplexer circuit has been designed and fabricated for US-CDMA handset applications. Meshed ground technology was newly applied to improve the quality factor of the embedded inductors for reducing the insertion loss of the quintplexer module. The proposed quintplexer module was comprised of passive triplexer, SAW duplexer for DCN band, and FBAR duplexer for US-PCS band. The passive triplexer circuit with 8 passive elements was comprised of a diplexer, parallel resonator, and matching network. A fabricated quintplexer module with meshed ground plane exhibited insertion losses of −2.2 dB/−2.8 dB at DCN Tx/Rx band, −2.8 dB/−3.2 dB at US-PCS Tx/Rx band, and −1.2 dB at GPS Rx band, respectively. In addition, the stop-band attenuation performances are −50 dB/−50 dB at DCN Tx/Rx band, −52 dB/−42 dB at PCS Tx/Rx band, and −35 dB at GPS Rx band, respectively. The applied meshed ground plane was confirmed to be effective for improving the quality factors of the embedded inductors resulting in low insertion loss and high isolation characteristics of the embedded triplexer circuit.

Ultra-Compact WiMAX Bandpass Filter Embedded Into a Printed Circuit Board With a

An ultra-compact bandpass filter has been developed for 2.3-2.7 GHz worldwide interoperability used for microwave access applications. The proposed filter was fully embedded into a multilayered printed circuit board (PCB) with a high dielectric strontium titanate (SrTiO3) composite film layer. In order to reduce the size of the filter and to avoid unwanted 3-D electromagnetic coupling between the embedded passive filter circuit elements, the proposed filter was designed using J-inverter transformation technology. Two grounding via inductors and a single grounding capacitor were also utilized to generate three independent finite transmission zeros to enhance the rejection characteristics at the proper frequency bands. Since the J-inverter transformed filter circuit elements could be designed with relatively small inductance and large capacitance values, the high dielectric composite film was highly effective in reducing the size and improving the performance of the filter. The high dielectric film exhibited a dielectric constant of 17, a tangent loss of 0.01, and a capacitance density of 12.2 pF/mm2 at 1 GHz. The measured maximum insertion loss in the passband ranged from 2.3 to 2.7 GHz was better than 1.8 dB, with a minimum value of 1.58 dB at 2.6 GHz. The return loss was higher than 15 dB in the passband. The transmission zeros occurred at 1.71 and 5.1 GHz, and provided suppressions of 45 dB at 1.71 GHz, and 54 dB at 5.1 GHz, respectively. The measured group delay was less than 0.8 ns in the passband. The embedded bandpass filter had a volume of 2.6 × 2.6 × 0.55 (H) mm3, which is the smallest one found, compared to previously reported devices, the filter, embedded into the eight-layered packaging substrate with the high dielectric composite layer, dramatically reduced the size up to 56%, and its performance was also much improved in comparison to the one embedded into a conventional six- layered PCB.

{\rm SrTiO}_{3}

In this paper, a MEMS tunable capacitor was successfully designed and fabricated using an aluminum nitride film and a gold suspended membrane with two air gap structure for commercial RF applications. Unlike conventional two-parallelplate tunable capacitors, the proposed tunable capacitor consists of one air suspended top electrode and two fixed bottom electrodes. One fixed and the top movable electrodes form a variable capacitor, while the other one provides necessary electrostatic actuation. The fabricated tunable capacitor exhibited a capacitance tuning range of 375% at 2 GHz, exceeding the theoretical limit of conventional twoparallel-plate tunable capacitors. In case of the contact state, the maximal quality factor was approximately 25 at 1.5 GHz. The developed fabrication process is also compatible with the existing standard IC (integrated circuit) technology, which makes it suitable for on chip intelligent transceivers and radios.

Composite Layer

Compact triple-band/quad mode FEM with newly designed triplexer circuit has been implemented for US-CDMA handset applications. The newly designed triplexer circuit was comprised of single diplexer, parallel resonant circuit, a BPF for GPS, and its impedance matching circuit. In comparison with previously reported triplexer circuit, it had much better performance characteristics and compact size, as expected. Most of simulated performance characteristic parameters were well matched with the measured ones. Since the fabricated triple-band/quad mode front-end module has good performance characteristics, small size/volume and low cost, it will be promising for US-CDMA handset applications. Their design and fabrication technologies will also be useful for advanced RF components and modules. In near future, on the basis of fabricated FEM, PCB embedded triple-band/quad mode FEM will be designed and demonstrated by using RF SOP technologies.

AlN Based RF MEMS Tunable Capacitor with Air-Suspended Electrode with Two Stages

In this paper, organic SIP based CDMA FEM has been designed, fabricated, optimized, and characterized by using organic SIP (system in a package) technology and resonant tank circuits. The proposed organic SIP based CDMA FEM is comprised of a PAM (power amplifier module), two LC resonant tank circuits, an output matching capacitive circuit, a SAW duplexer, and a multi-layered organic substrate. The LC resonant tank is newly applied in the DC bias circuits of the proposed FEM in order to reduce the inductance values and to improve ACPR instead of conventional RF choke inductor. The fabricated FEM has a gain of 25.9dB, DC supply current of 387mA at 25dBm, ACPR1 of -50.8dBc at 885kHz, ACPR2 of -56.3dBc at 1980kHz, and PAE of 24% at 25dBm, respectively. The volume of the fabricated FEM is approximately 6mm times 5mm times 1.3mm (height)

Compact triple band/quad mode front-end module for US-CDMA handset applications

In this study, a micro-fabricated multi-resonant capacitive switch with high isolation was successfully designed and fabricated for ultra wide band (UWB) system ranging from 3- to 10-GHz. To achieve the high isolation and wide frequency bandwidth, three capacitive shunt membranes and meander inductors were utilized to design the switch with three LC resonant switching circuits. And also, aluminum nitride film (AlN) was applied to increase on/off capacitance ratio of the micro-fabricated capacitive switch. The dielectric constant and tangent loss of the AlN film were 8.8 and 0.008, respectively. The measured on-state and off-state capacitances of each capacitive shunt switch were approximately 52 fF and 3.1 pF. The capacitance ratio was approximately 59. The fabricated resonant switch exhibited the high isolation of over 30dB at the frequencies ranging from 5- to 10-GHz and 70 dB at 6.5GHz. The size and volume of the fabricated switch were approximately 1.4 × 1.7 × 0.0083 (H) mm3.

Organic SIP based CDMA FEM with LC Resonant Tank Circuit

In this paper, a highly miniaturized and performed UWB bandpass filter has been newly designed and implemented by embedding all the passive elements into a multi-layered PCB substrate with high dielectric SrTiO3 composite film for 3.1 - 4.75 GHz compact UWB system applications. The high dielectric composite film was utilized to increase the capacitance densities and quality factors of capacitors embedded into the PCB. In order to reduce the size of the filter and avoid parasitic EM coupling between the embedded filter circuit elements, it was designed by using a 3 rd order Chebyshev circuit topology and a capacitive coupled transformation technology. Independent transmission zeros were also applied for improving the attenuation of the filter at the desired stopbands. The measured insertion and return losses in the passband were better than 1.68 and 12 dB, with a minimum value of 0.78 dB. The transmission zeros of the measured response were occurred at 2.2 and 5.15 GHz resulting in excellent suppressions of 31 and 20 dB at WLAN bands of 2.4 and 5.15 GHz, respectively. The size of the fabricated bandpass filter was 2.9 x 2.8 x 0.55 (H) mm 3 .

Micro-fabricated multi-resonant capacitive switch for UWB applications

In this paper, a highly miniaturized dual-band band pass filter using independent band stop resonators has been newly designed and fabricated by embedding all the passive lumped elements into a low-temperature co-fired ceramic (LTCC) substrate for 2.4 to 2.5 GHz (802.11b) and 5.15 to 5.85 GHz (802.11a/g) wireless LAN system applications. In order to reduce a size/volume of the filter and avoid electromagnetic parasitic couplings between the embedded passive elements, the proposed filter was designed by using 3rd order Chebyshev circuit topology and J-inverter transformation technology. The 3rd order Chebyshev band pass filter was firstly realized for 802.11b frequency band selection and it was transformed by using finite transmission zeros technology to minimize the electromagnetic coupling. Finally a dual-band filter was realized by constructing 802.11a/g WLAN band selection filter by adding independent band stop resonators into the 802.11b filter circuit. The measured maximum insertion losses in the lower and higher pass-bands were better than 2.0 dB and 1.3 dB with minimum return losses of 15 dB and 14 dB, respectively. The overall size/volume of the fabricated filter was 2.7 × 2.3 × 0.68 mm3 which was the smallest one in the previously reported devices.