диафрагмированные волноводные фильтры / fbc2a57c-dbe8-41e7-94e9-3386a33ab18e

related to the slot opening, where strong electric fields occur, disposed to the left-hand side of slot 1.

At 2500 MHz, a representative frequency in the high band, stronger radiation to the 1y direction in the x–y plane and y-z plane is seen. This is different from that observed at 800 MHz, and is largely related the slot opening disposed to the right-hand side of slot 2. In the x–z plane, however, symmetric radiation pattern is also generally seen as that observed at 800 MHz.

4. CONCLUSION

A low-profile (7 mm only) open-slot antenna for the table device application has been proposed and studied. The antenna is capable of providing two wide operating bands for the LTE/ WWAN operation in the 698–960/1710–2690 MHz bands. The antenna uses two IL open slots and two feeds with wideband matching circuits. Owing to its low profile, the antenna is promising to be disposed in a narrow spacing between the display panel and the top or bottom edge of the tablet device. The operating principle of the proposed antenna to generate two wide operating bands has been presented. Acceptable radiation characteristics of the antenna for mobile communication applications have also been obtained.

REFERENCES

1.K.L. Wong and T.W. Weng, Very-low-profile dual-wideband tablet device antenna for LTE/WWAN operation, Microwave Opt Technol Lett 56 (2014), 1938–1942.

2.K.L. Wong and M.T. Chen, Very-low-profile dual-wideband loop antenna for LTE tablet computer, Microwave Opt Technol Lett 57 (2015), 141–146.

3.K.L. Wong, P.W. Lin, and C.H. Chang, Simple printed monopole slot antenna for penta-band WWAN operation in the mobile handset, Microwave Opt Technol Lett 53 (2011), 1399–1404.

4.H. Wang, M. Zheng, and S.Q. Zhang, Monopole slot antenna, U.S. Patent 6,618,020 B2, 2003.

5.P.L. Sun, H.K. Dai, and C.H. Huang, Dual band slot antenna with single feed line, U.S. Patent 6,677,909 B2, 2004.

6.C.I. Lin and K.L. Wong, Printed monopole slot antenna for internal multiband mobile phone antenna, IEEE Trans Antennas Propag 55 (2007), 3690–3697.

7.Z. Liu and K. Boyle, Bandwidth enhancement of a quarterwavelength slot antenna by capacitive loading, Microwave Opt Technol Lett 51 (2009), 2114–2116.

8.K.L. Wong and L.C. Lee, Multiband printed monopole slot antenna for WWAN operation in the laptop computer, IEEE Trans Antennas Propag 57 (2009), 324–330.

9.Y.W. Chi and K.L. Wong, Quarter-wavelength printed loop antenna with an internal printed matching circuit for GSM/DCS/PCS/UMTS operation in the mobile phone, IEEE Trans Antennas Propag 57 (2009), 2541–2547.

10.W. Dou, S. Senatore, and A. Zarnowitz, Internal diversity antenna architecture, U.S. Patent 7,940,223 B2, 2011.

11.V. Plicanic, B.K. Lau, A. Derneryd, and Z. Ying, Actual diversity performance of a multiband diversity antenna with hand and head effects, IEEE Trans Antennas Propag 57 (2009), 1547–1556.

12.K.L. Wong, T.W. Kang, and M.F. Tu, Internal mobile phone antenna array for LTE/WWAN and LTE MIMO operations, Microwave Opt Technol Lett 53 (2011), 1569–1573.

13.K.L. Wong, W.Y. Chen, and T.W. Kang, On-board printed coupledfed loop antenna in close proximity to the surrounding ground plane for penta-band WWAN mobile phone, IEEE Trans Antennas Propag 59 (2011), 751–757.

14.Z. Liu and K. Boyle, Antenna arrangement and a radio apparatus including the antenna arrangement, U.S. Patent 8,638,266 B2, 2014.

15.K.L. Wong and W.J. Lin, WWAN/LTE printed slot antenna for tablet computer application, Microwave Opt Technol Lett 54 (2012), 44–49.

16.F.H. Chu and K.L. Wong, Simple folded monopole slot antenna for penta-band clamshell mobile phone application, IEEE Trans Antennas Propag 57 (2009), 3680–3684.

17.K.L. Wong and L.Y. Chen, Small-size LTE/WWAN tablet device antenna with two hybrid feeds, IEEE Trans Antennas Propag 62 (2014), 2926–2934.

18.K.L. Wong and C.Y. Tsai, Small-size stacked inverted-F antenna with two hybrid shorting strips for the LTE/WWAN tablet device, IEEE Trans Antennas Propag 62 (2014), 3962–3969.

19.ANSYS high frequency structure syntehsizer (HFSS), Pittsburgh, PA, Available at http://www.ansys.com/products/hf/hfss/

20.K.L. Wong and M.T. Chen, Small-size LTE/WWAN printed loop antenna with an inductively coupled branch strip for bandwidth enhancement in the tablet computer, IEEE Trans Antennas Propag 61 (2013), 6144–6151.

21.K.L. Wong and T.W. Weng, Small-size triple-wideband LTE/ WWAN tablet device antenna, IEEE Antennas Wireless Propag Lett 12 (2013), 1516–1519.

VC 2015 Wiley Periodicals, Inc.

MINIATURIZED BANDPASS SUBSTRATE INTEGRATED WAVEGUIDE FILTER WITH FREQUENCY-DEPENDENT COUPLING REALIZED USING ASYMMETRIC GCPW DISCONTINUITY

Andrzej Jedrzejewski, Lukasz Szydlowski, and Michał Mrozowski

Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 11/12 Gabriela Narutowicza Street, 80-233 Gdansk, Poland; Corresponding author: andrzej.jedrzejewski87@ gmail.com

Received 12 January 2015

ABSTRACT: An asymmetric GCPW discontinuity is proposed to provide frequency-dependent coupling in microwave bandpass filters. Wider and narrow sections introduce, respectively, the capacitive and inductive component to the equivalent circuit representing coupling. By selecting the dimensions of the discontinuity and width of the inductive window in substrate integrated waveguide, an additional transmission zero can be introduced at prescribed positions. A distinct feature of the proposed structure is a small footprint and low loss. As an example, a bandpass filter with a central frequency of 4.6 GHz and a 200 MHz passband is designed, and its performance is measured. VC 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1818–1821, 2015; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29203

Key words: substrate integrated waveguide technology; bandpass filters; frequency-dependent coupling; asymmetric GCPW discontinuity; miniaturized filter

1. INTRODUCTION

Substrate integrated waveguide (SIW) [1,2] is a relatively new concept in microwave engineering that has been proposed to overcome the drawbacks of the conventional metallic waveguides, such as large size and weight and at the same time to achieve better performance at higher frequencies than microstrip. The SIW is a type of waveguide that is integrated in the double-side metallized dielectric substrate with two rows of metallized via holes acting as narrow walls of the guide. This construction provides an easy integration with planar circuitry, good shielding, low loss, low-profile, low-cost, and low-weight scheme while maintaining high performance, which is particularly useful for the airborne and satellite system applications.

where x is the normalized angular frequency. When the impedance matrix is known the next step is dimensional synthesis of a distributed implementation of the filter.

Constant couplings are implemented as well-known inductive irises while the frequency-dependent coupling is realized as

an asymmetric GCPW discontinuity. The GCPW discontinuity provides an easy control of the transmission zero position (Fig. 2), low loss, and small footprint. The dimensions for resonators

Figure 1 Lumped-element (a) and distributed (b) model of the asymmetric GCPW discontinuity. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

Figure 2 Example characteristics of an asymmetric GCPW discontinuity showing the possibility of adjusting position of a transmission zero. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

Figure 3 Example impedance characteristics of dispersive coupling with positive slope. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

Figure 4 Ideal prototype filter response (topology shown in the inset)

and constant couplings were found in a well-known manner based of resonant frequencies. To synthesize the dispersive coupling, we have adopted the technique presented in Ref. 7, which takes into account not only the resonance peaks of two coupled resonators, but also the position of the transmission zero (antiresonance). The final numerical tunning is done by a built-in HFSS

Figure 5 Layout of the filter, the slot width is 0.3 and distance between slots is 0.3 (units: mm). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

Figure 6 Comparison between measured (solid line) and simulated (dashed line) responses of the three pole generalized Chebyshev filter with an asymmetric GCPW discontinuity. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

optimizer with the sequential nonlinear programming algorithm. The final dimensions are shown in Figure 5. The result of fullwave simulation is depicted in Figure 6 as the dashed lines.

3. EXPERIMENTAL VERIFICATION

The filter was fabricated on a Taconic RF-35 substrate with the loss tangent equal to 0.0018 at 1.9 GHz. The permittivity and height of the substrate are er 53.5 and h 50.762 mm, respectively. Each via hole has a diameter of d 51 mm and the spacing between their centers equals 1.5 mm. A comparison between the measured and simulated data is shown in Figure 6. The return loss level is equal to 20.8 dB. The filter band and center frequency moved down by 20 MHz due to the inaccurate fabrication of the filter and permittivity deviation. The position of the first transmission zero is moved down by approximately 120 MHz, and the position of the second transmission zero is moved down by 10 MHz. The average insertion loss level is around 1.9 dB, as a result of the dielectric and conductor loss and the poor metalization of the via holes. The average radiation loss from the GCPW discontinuity equals 0.2 dB. A photograph of the fabricated filter is shown in the inset in Figure 7. Also in Figure 7, the

Figure 7 Out-of-band filter performance (a photo of the fabricated filter in the inset). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

out-of-band filter performance is presented. It can be observed that the spurious resonance resulting from the GCPW discontinuity occurs at 3.5 GHz; however, transmission at this point does not exceed 224 dB.

4. CONCLUSION

This article presented a generalized Chebyshev filter in triplet configuration with frequency-dependent coupling realized as an asymmetric GCPW discontinuity. The measurements showed good agreement with the simulated data, thus, validating the proposed discontinuity.

ACKNOWLEDGMENT

This work was funded by the Polish National Science Centre under contract DEC 2011/01/B/ST7/06634.

REFERENCES

1.D. Deslandes and K. Wu, Accurate modeling, wave mechanisms, and design considerations of a substrate integrated waveguide, IEEE Trans Microwave Theory Tech 54 (2006), 2516–2526.

2.M. Bozzi, A. Georgiadis, and K. Wu, Review of substrate-integrated waveguide circuits and antennas, IET Microwave Antennas Propag 5 (2011), 909–920.

3.S. Amari and J. Bornemann, Using frequency-dependent coupling to generate finite attenuation poles in direct-coupled resonator bandpass filters, IEEE Microwave Guided Wave Lett 9 (1999), 404–406.

4.W. Meng, H. Lee, K.A. Zaki, and A.E. Atia, Synthesis of multicoupled resonator filters with frequency-dependent couplings, In: IEEE MTT-S International Microwave Symposium Digest (MTT), Anaheim, CA, 2010, pp. 1716–1719.

5.L. Szydlowski, A. Lamecki, and M. Mrozowski, Coupled-resonator filters with frequency-dependent couplings: coupling matrix synthesis, IEEE Microwave Wireless Compon Lett 22 (2012), 312–314.

6.A. Jedrzejewski, N. Leszczynska, L. Szydlowski, and M. Mrozowski, Zero-pole approach to computer aided design of in-line SIW filters with transmission zeros, Prog Electromagn Res 131 (2012), 517–533

7.L. Szydlowski, N. Leszczynska, A. Lamecki, and M. Mrozowski, A substrate integrated waveguide (siw) bandpass filter in a box configuration with frequency-dependent coupling, IEEE Microwave Wireless Compon Lett 2012, (11), pp. 556,558

8.S. Wei, W. Lin-Sheng, S. Xiao-Wei, Y. Wen-Yan, and M. Jun-Fa, Novel substrate integrated waveguide filters with mixed cross coupling (mcc), IEEE Microwave Wireless Compon Lett 19 (2009), pp.701–703.

9.L. Szydlowski, N. Leszczynska, and M. Mrozowski, A linear phase filter in quadruplet topology with frequency-dependent couplings, IEEE Microwave Wireless Compon Lett 24 (2014), 32–34.

VC 2015 Wiley Periodicals, Inc.

BPF INTEGRATED AMPLIFIER MODULE USING LTCC TECHNOLOGY FOR MILLIMETER-WAVE APPLICATIONS

Young Chul Lee,1 Yun Hee Cho,2 and Chul Soon Park3

1Department of Electronic Engineering, Mokpo National Maritime University (MMU), 91 Haeyangdaehak-ro, Mokpo-si, South Korea; Corresponding author: leeyc@mmu.ac.kr

2Technical Research & Development Center, Hyundai Mobis, Mabuk-dong, Giheung-gu, Yongin-si, Gyeonggi-do, Korea

3Department of Electrical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea

Received 16 January 2015

ABSTRACT: A compact amplifier module integrating a low-loss stripline (SL) band-pass filter (BPF) using low-temperature cofired ceramic (LTCC) technology is presented for millimeter-wave (mm-wave) applica-

tions. A parasitic resonance-free SL BPF is proposed by modifying a distribution of ground vias in the SL LTCC BPF. The SL BPF fabricated in the 6 LTCC layers showed a 3-dB bandwidth of 8.4% at the center frequency of 41.8 GHz. Its measured insertion and return loss were as small as 1.7 dB and 10.2 dB, respectively. The SL BPF integrated amplifier LTCC module was implemented in the single LTCC substrate in a size of 11.3 3 12.2 3 0.6 mm3. Its gain of 10 dB and output power of 18 dBm is achieved in the pass band from 39.5 to 42 GHz. VC 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1821–1825, 2015; View this article online at wileyonlinelibrary.com. DOI 10.1002/ mop.29206

Key words: low-temperature cofired ceramic; amplifier module; parasitic waveguide; stripline band-pass filter

1. INTRODUCTION

In general, millimeter-wave (mm-wave) band from 30 to 300 GHz is favored to achieve the high-speed data transmission because of great amount of available bandwidth in the communication systems. Several applications [1–3] in mm-wave band have been developed in the last decade. One of the most important issues for an implementation of mm-wave systems is the miniaturization of the systems as well as multifunctionality and low-cost fabrication. The low-temperature cofired ceramics (LTCC) technology has been applied to compact module implementation because of its three-dimensional (3D) integration capability, excellent metal conductivity, low-loss characteristics, and a temperature coefficient of expansion close to semiconductors [4].

The progress over the past 10 years has been formidable in the LTCC-based module technology. Although various LTCC components [5,6] and modules [7,8] have been proposed and implemented, the band-pass filter (BPF) still remains one of the important passive components because of its function in the radio system and its area occupied in the 3D miniaturized LTCC module. In order for BPFs to be fully embedded in the LTCC module [4], several structures such as multilayer transitions [9] and internal ground (GND) planes have been used. However, these complicated structures can make parasitic transmission lines [10–12] such as a rectangular or parallel plate waveguides (WG) in the module. If they generate unwanted resonant modes in the frequency band for the module operation, it malfunctions. Although, many LTCC-based modules [4–8] embedding diverse passive and active components have been reported, parasitic resonant issues have been rarely mentioned.

In this work, a 40 GHz amplifier LTCC module integrating a low-loss stripline (SL) BPF has been presented for mm-wave applications. To eliminate the unwanted resonances, the distribution of the ground vias in the SL BPF has been proposed. Finally, utilizing a wire-bonding interconnection, the amplifier monolithic microwave integrated circuit (MMIC) is integrated with the resonance-free BPF and its measured losses and output power are characterized.

2. LTCC AMPLIFIER MODULE DESIGN

Figure 1 shows a cross-sectional view of the amplifier LTCC module consisting of the amplifier MMIC, the fully embedded SL BPF, off-chip components for DC bias, and transitions. The CPW and SL are used as a signal line, because their wide ground planes provide effective shielding from electromagnetic (EM) interferences. However, the amplifier and BPF are connected using the vertical via transition and impedance matching circuits due to different structures of the signal paths and discontinuity, respectively. For isolation of each layer, internal