Ultra-low-profile small-size LTCC front-end module (FEM) for WLAN applications based on a novel diplexer design approach

Abstract

in many wireless communication systems, and they have been reported already [8]. Figure 6 shows the circuit schematic of a lumped element Ttype balun which an additional LC resonator. The LC resonator is used to achieve attenuation in second harmonic band. Figure 7 shows the measured performance of the implemented balun. The balun has an insertion loss of less than 0.9 dB, a return loss of more than 16.8 dB, an amplitude imbalance of 0.2 dB, and a phase difference of 175. 1-171.6 in the frequency range of 2.4-2.5 GHz. The good agreement between measured and simulated results is observed, as shown in Figure 7. The fabricated balun has seven pattern layers and the physical size is 1.7 Â 1.7 Â 0.44 mm 3 . RF FRONT-END MODULEThe proposed single-band RF FEM is implemented by combining a novel selectable filter with balun, and two PIN diodes for Tx and Rx path selection. Also, DC block capacitors are placed on top substrate. Figure 8 illustrates three-dimensional view and photograph of the fabricated single-band RF FEM. The LTCC substrate, which used in manufacturing the proposed RF FEM had a dielectric constant of 9.0, a loss tangent of 0.005 and a thickness of 40 lm. After cofiring, the thickness of the sheet had been 22 lm. The number of pattern layer in the fabricated RF FEM is nine including two inner grounds, and its thickness is 440 lm. The overall size of the module is less than 2.3 Â 4.0 mm 2 . The measured result of the RF FEM is shown in Figure 9. In case of Tx path, 2-GHz band has an insertion loss of 2.3 dB, an amplitude imbalance of 0.6 dB, a return loss of more than 16.8 dB and a phase difference of 177-171.7 . The second harmonic suppression is more than 39.7 dB in the frequency range of 4.8-5.0 GHz. In case of Rx path, 2-GHz band has an insertion loss of less than 1.2 dB, and a return loss of more than 16.7 dB. CONCLUSIONSIn this article, the compact and novel integrated single-band RF FEM for wireless communication system has been designed and implemented using LTCC technology. All passive components in a novel selectable filter are fully embedded in the substrate. The fabricated filter has seven pattern layers and it occupies less than 2.3 Â 2.3 Â 0.44 mm 3 . The measured results of the implemented filter are in good agreement with the simulated results. The implemented filter has low insertion loss and high attenuation at other passband. The RF FEM was realized by the proposed selectable filter with two PIN diodes at each output port for selecting Tx or Rx mode, and balun. It provided relatively low loss and occupied only 2.3 Â 4.0 Â 0.44 mm 3 . The proposed RF FEM can be low-loss and low-cost solution by removing MMIC SPDT switch in series connection. ABSTRACT: The analysis and design of an omnidirectional antenna that functions over a very broad frequency band is presented. Design guidelines for this antenna have been derived using electromagnetic analysis software. Measured results of a prototype developed according to these guidelines are presented. These results are compared to simulation...

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“…Therefore, it is suited for compact wireless communication module realization. Reflecting these trends, several research groups have implemented compact and integrated RF front‐end modules (FEMs) using the LTCC technology [1–7].…”

Design for SAW Antenna-Plexers with Improved Matching Inductance Circuits

“…Acoustic wave (AW) filter modules are key components [ 2 ], but their performance degrades as frequency increases [ 3 ]. Compact RF passive components are realized by using low-temperature co-fired ceramic (LTCC) technologies, including diplexers [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ], duplexers [ 11 , 12 , 13 ], band stop filters [ 14 , 15 ], and low pass filters [ 16 ]. However, when overall space constraints are considered, this may not be a suitable solution for a mobile phone.…”

A novel single‐band RF front‐end module for wireless communication systems

“…Therefore, it is suited for compact wireless communication module realization. Reflecting these trends, several research groups have implemented compact and integrated RF front‐end modules (FEMs) using the LTCC technology [1–7].…”