Multilayer Liquid Crystal Polymer Substrate Research Articles

Compact Integrated Lumped-Element Bandpass Filter Loaded with Defected Ground Structure Based on Multilayer Liquid Crystal Polymer Substrate

Compact Integrated Lumped-Element Bandpass Filter Loaded with Defected Ground Structure Based on Multilayer Liquid Crystal Polymer Substrate

Broadband SIW-to-Waveguide Transition in Multilayer LCP Substrates at W-Band

In this letter, we present a substrate-integrated waveguide (SIW) to air-filled rectangular waveguide (WG) transition in multilayer liquid crystal polymer substrates at W-band. The proposed transition is achieved by using a SIW-fed linearly flared antipodal slot line inserted into a WG. To minimize packaging leakage, no guided vias are utilized in the slot line region. Full-wave simulation reveals a low insertion loss of 0.8 dB for the proposed transition at W-band. To experimentally demonstrate this design, a WG-to-SIW-to-WG transition was fabricated and characterized. The measured insertion and reflection loss of the back-to-back transition is less than 1.8 and −11 dB, respectively, at W-band.

Slot-Coupled Directional Filters in Multilayer LCP Substrates at 95 GHz

In this paper, traveling-wave directional filters (DFs) in multilayer liquid crystal polymer substrates were proposed at 95 GHz, consisting of two terminating microstrip lines (MSLs) in the top circuit layer, a shared ground and coupling slots in the second layer, and MSL loop resonators in the bottom layer. By using asymmetric phase topology for the loop, the proposed DFs address higher directivity and Q-factor over the traditional symmetric traveling-wave DFs. The single-loop DF was demonstrated with a 3-dB passband width of 4.8% and an insertion loss of 4.6 dB at 94 GHz. To improve the directivity, particularly the insertion loss, two identical DFs were cascaded in series in the direction of the terminating lines. A bandwidth of 8% and a low insertion loss of 2.6 dB can be obtained with a phase delay of 360° between the two DFs. Limited by the practical application, the proposed DFs were fabricated and demonstrated in hybrid substrates, which slightly increases the insertion loss. The measured insertion loss of the single-loop and double-loop DFs is 5.2 and 3.1 dB at 95 GHz, respectively, showing good agreement with the simulated data.

23:1 Bandwidth ratio quasi‐lumped component balun on a multilayer organic substrate

Author(s): Pham, BL; Ta, HH; Pham, AV; Leoni, RE; Leviatan, Y | Abstract: In this study, the authors present the design and development of a novel ultra-wideband coupled-line balun on a multilayer liquid crystal polymer substrate. The balun is designed using a quarter wavelength (λ/4) asymmetric broadside coupled line. The defected ground structure and a lumped phase compensation circuit are developed to achieve wide bandwidth performance for the balun. The balun has a measured bandwidth ratio of 23:1, from 80 to 1860 MHz. Within the operating bandwidth, the experimental results demonstrate that the balun achieves an input return loss of better than 10 dB, an insertion loss of better than 1 dB, an amplitude imbalance of better than ±0.4 dB and a phase imbalance of better than ±10°. The size of the balun is 40.64 mm × 40.64 mm or 0.22 λg × 0.22 λg, where λg is the guided wavelength at the centre frequency of 970 MHz.

Parallel-coupled stub-loaded resonator bandpass filter with ultra-wideband passband on multilayer liquid crystal polymer substrates

A multilayer bandpass filter with ultra-wideband passband is presented in this paper. The filter is designed to have a very wide passband with a fractional bandwidth of about 180% at a center frequency of 10.5 GHz. The filter consists of two sections of parallel-coupled lines loaded at the center with short-circuited stub. Each of the coupled line sections and short-circuited stubs is designed to be a quarter-wavelength long at the desired center frequency. As a result, the filter exhibited a selective filtering characteristic equivalent to a five-pole Chebyshev filter with a very low insertion loss. The proposed filter is realized and fabricated using multilayer liquid crystal polymer substrate. The design is successfully realized in theory and verified by full-wave electromagnetic simulation of the full layout and the experiment where excellent agreement is obtained.

Ultrawide band CBCPW to stripline vertical transition in multilayer LCP substrates

This article presents an improved design of conductor-backed coplanar waveguide (CBCPW)-to-stripline (SL) vertical transition in multilayer liquid crystal polymer substrates. The CBCPW and SL is designed on the top and second conductor layers, respectively, and electrically connected with each other through micro-vias. The reported transition is optimized using High Frequency Simulation Software, and the simulated results predict low loss over an ultrawide bandwidth. To validate our design, a CBCPW-to-SL-to-CBCPW transition was fabricated and characterized. The back-to-back transition shows an insertion loss of less than 2.5 dB and a return loss of less than −10 dB over a frequency band from DC to 78 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1481–1484, 2015

A Compact Broadband Balun on Multilayer Organic Substrate

We present the design and development of a compact, broadband balun based on a quasi-lumped LC transformer. The balun is constructed on a multilayer liquid crystal polymer substrate. The balun has a wide range of operating frequency from 0.9 to 3.6 GHz. Within this operating band, the balun achieves a measured insertion loss of less than 1 dB, a measured return loss of better than 10 dB, a measured amplitude imbalance of less than 1 dB and a measured phase imbalance less than 7°. This balun has an extremely compact size of 2 × 2.5 mm2. Copyright © 2013 Wiley Periodicals, Inc.

Ultra-wideband bandpass filter with multiple notch-bands on multilayer liquid crystal polymer substrate

Novel compact ultra-wideband (UWB) bandpass filters (BPFs) with single or multiple notch-bands to avoid interference from existing radio systems are presented. A compact UWB BPF is proposed and designed based on broadside-coupled stepped impedance resonators (SIRs) at first, and then notch-bands are generated by embedding open-circuit stubs into broadside-coupled SIRs. Because of the harmonic suppression behaviour of SIRs, the proposed UWB BPFs have a wide stopband and high rejection level. The characteristic of the proposed notch-structure was investigated by full-wave simulations. Multilayer liquid crystal polymer (LCP) technology was used to implement the designed UWB BPFs. In the experiments, a UWB BPF with excellent stopband performance was designed to meet the Federal communications commission-defined indoor limits at first, and then UWB BPFs with single, double and triple notch-bands were designed to demonstrate the flexible notch-band, high-selectivity and wideband harmonic suppression performances of the proposed filter. The designed BPFs were fabricated by a multilayer LCP lamination process and measured using a vector network analyser. Good agreement between the predicted and measured results was obtained as presented here.

Compact ultra-wideband bandpass filter using broadside coupled hairpin structures on multilayer liquid crystal polymer substrate

A novel ultra-wideband (UWB) bandpass filter (BPF) using a broadside-coupled hairpin structure and multilayer organic liquid crystal polymer (LCP) technology is presented. To suppress stopband harmonic response, folded stepped impedance structures were adopted as hairpin resonators in the design. The proposed filter has been investigated numerically and experimentally. Multilayer LCP technology was used to implement designed UWB BPF. Good agreement between simulated and measured results of the proposed filter was observed. They show that the fabricated UWB BPF has a good performance, including a small insertion loss, a flat group delay with a variation within 0.1 ns in most of its passband, a wide stopband from 11.0 20.0 GHz with a high rejection level up to 20.0 dB, and a very compact size of 9.8 times 7.5 mm (0.36 lambdag times 0.27 lambdag, where lambdag is the guided wavelength of 50 Omega microstrip line at 6.85 GHz).

Packaging of MMICs in multilayer LCP substrates

A 13-25-GHz GaAs bare die low noise amplifier is embedded inside a multilayer liquid crystal polymer (LCP) package made from seven layers of thin-film LCP. This new packaging topology has inherently unique properties that could make it an attractive alternative in some instances to traditional metal and ceramic hermetic packages. LCP is a near-hermetic material and its lamination process is at a relatively low temperature (285degC versus >800degC for ceramics). The active device is enclosed in a package consisting of several laminated C02 laser machined LCP superstrate layers. Measurements demonstrate that the LCP package and the 285degC packaging process have minimal effects on the monolithic microwave integrated circuit radio frequency (RF) performance. These findings show that both active and passive devices can be integrated together in a homogeneous laminated multilayer LCP package. This active/passive compatibility demonstrates a unique capability of LCP to form compact, vertically integrated (3-D) RF system-on-a-package modules