{"id":5465,"date":"2014-07-10T19:42:36","date_gmt":"2014-07-10T15:42:36","guid":{"rendered":"https:\/\/butis-m.ru\/?p=5465"},"modified":"2014-08-17T11:22:01","modified_gmt":"2014-08-17T07:22:01","slug":"wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications","status":"publish","type":"post","link":"https:\/\/butis-m.ru\/en\/articles-en\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\/","title":{"rendered":"Wideband low loss SAW filters for telecommunication and mobile radio applications"},"content":{"rendered":"<p style=\"text-align: justify;\">The possibility of utilizing cuts of LiNbO3\u00a0with high piezoelectric coupling for leaky waves - 41\u00b0-YX and 49\u00b0-YX - in wideband SAW filters, has been\u00a0demonstrated. The equivalent circuit model was\u00a0modified for longitudinally coupled resonator filters and\u00a0some second-order effects have been taken into account\u00a0to improve the accuracy of filter simulation. Thick Al\u00a0electrodes are used to increase the effective\u00a0electromechanical coupling. Spurious SAW signals are\u00a0suppressed by the frequency shift between filter\u00a0cascades. Low-loss (2-3 dB) two-cascade filters with\u00a0bandwidths 6-7% and high sidelobe suppression (60 dB),\u00a0more typical for three-cascade filters, were designed and\u00a0manufactured.<\/p>\n<h2 style=\"text-align: justify;\">INTRODUCTION<\/h2>\n<p style=\"text-align: justify;\">Cordless and cellular phone systems are the most\u00a0rapidly growing areas of modern telecommunication.\u00a0The dynamic market of compact mobile\u00a0communication systems have greatly stimulated the\u00a0new SAW design techniques, such as SAW coupled\u00a0resonator filters [1]. The impressive results were\u00a0achieved in low-loss longitudinally coupled resonator\u00a0filters (LCRF) utilizing 36\u00b0-YX cut of LiTaO3 or\u00a064\u00b0-YX cut of LiNbO3. Due to high electromechanical\u00a0coupling for leaky waves propagating in\u00a0these cuts (5% and 11%), the obtainable bandwidths\u00a0are about 2 and 4%, respectively, which meet many\u00a0RF and IF requirements for compact mobile and\u00a0cellular communication systems. However, the recent\u00a0tendencies of using more complicated signals and\u00a0increasing the variety of service functions in these\u00a0systems demand low-loss filters with wider\u00a0bandwidth, up to 10%, and sufficiently high sidelobe\u00a0suppression, about 60 dB.<\/p>\n<p style=\"text-align: justify;\">This problem can be partially solved by\u00a0complexity of filter structures and\/or fabrication\u00a0process[2]. But the most efficient way is to utilize the\u00a0substrate with higher electromechanical coupling,\u00a0for example, 41\u00b0-YX LiNbO3, having k2=17.2% or\u00a049\u00b0-YX LiNbO3, k2=15.7% (see, for example, table 1\u00a0in [3]). The main drawback for these cuts is higher\u00a0conversion of leaky SAW into bulk waves. Forexample, while the electrode thickness h\/l is about0.04, the normalized value of absorption coefficient\u00a0is 0.65 in 41\u00b0-YX LiNbO3 compared to 0.21 in 64\u00b0-YX LiNbO3 [4]. One more drawback is higher\u00a0coupling for Rayleigh SAW, which is a spurious\u00a0signal here and leads to degradation of filter\u00a0selectivity to 35-40 dB. The last parameter may be\u00a0improved to 50 dB by increasing the number of\u00a0cascades, but in such structure insertion loss becomes\u00a0higher by 0.8-1.0 dB. In addition, the obtainable\u00a0bandwidth is reduced and the filter size is increased.<\/p>\n<p style=\"text-align: justify;\">This paper presents the results of optimization for\u00a0two-cascade resonator filters with center frequencies\u00a0400-500 MHz, fractional bandwidth 6-7% and\u00a0sidelobe suppression about 60 dB, based on 41\u00b0-YX\u00a0and 49\u00b0-YX cuts of LiNbO3 . The filters are smaller\u00a0compared to three-cascade variant and less sensitive\u00a0to technological variations in mass production.<\/p>\n<h2 style=\"text-align: justify;\">DESCRIPTION OF MODEL<\/h2>\n<p style=\"text-align: justify;\">Fig.1 shows a structure of LCRF comprising three\u00a0interdigital transducers (IDTs). This structure is\u00a0considered as an example. The profiles of 1st and 3rd\u00a0modes which are the fundamental modes and<br \/>\ndetermine the filter performance, are also shown in\u00a0Fig.1 The well known cross-field Mason-Smith\u00a0equivalent circuit model has been modified for\u00a0LCRF design. The model accuracy has been\u00a0improved by taking into account the following\u00a0second-order effects:<\/p>\n<ul>\n<li>electrode reflections;<\/li>\n<li>charge distribution on IDT electrodes;<\/li>\n<li>energy storage effect;<\/li>\n<li>propagation loss and energy loss because of<\/li>\n<li>scattering into bulk waves;<\/li>\n<li>electrode resistivity;<\/li>\n<li>electromagnetic cross-talk.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\">The filter response is simulated for arbitrary\u00a0values of generator and load impedances. External\u00a0circuits include matching elements and spurious\u00a0coupling at the input and the output filter ports.\u00a0Analytical expressions are used to account for\u00a0dependencies of substrate parameters on metallization\u00a0thickness and frequency, their coefficients being\u00a0obtained from experimental data.<\/p>\n<div id=\"attachment_5496\" style=\"width: 295px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic88.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5496\" class=\"size-full wp-image-5496\" src=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic88.jpg\" alt=\"Fig. 1 The structure of resonator cascade and\u00a0configuration of 1-st and 3-rd modes.\" width=\"285\" height=\"251\" \/><\/a><p id=\"caption-attachment-5496\" class=\"wp-caption-text\">Fig. 1 The structure of resonator cascade and\u00a0configuration of 1-st and 3-rd modes.<\/p><\/div>\n<div id=\"attachment_5494\" style=\"width: 363px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic89.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5494\" class=\"size-full wp-image-5494\" src=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic89.jpg\" alt=\"Fig.2 The experimental frequency response\u00a0\u00bdS21\u00bd of 442 MHz resonator filter on the substrate\u00a0of 64\u00b0 -YX LiNbO3 . Insertion loss is 2.9 dB,\u00a0fractional bandwidth is 4.3%.\" width=\"353\" height=\"297\" \/><\/a><p id=\"caption-attachment-5494\" class=\"wp-caption-text\">Fig.2 The experimental frequency response\u00a0\u00bdS21\u00bd of 442 MHz resonator filter on the substrate\u00a0of 64\u00b0 -YX LiNbO3 . Insertion loss is 2.9 dB,\u00a0fractional bandwidth is 4.3%.<\/p><\/div>\n<p style=\"text-align: justify;\">Therefore, a fine tuning of the model was achieved\u00a0while simulating frequency dependencies of scattering\u00a0matrix coefficients S21 and S11, group delay time,\u00a0input and output impedances of resonator filters (the\u00a01st\/2nd and the 1st\/3rd mode configurations). 2-pole,\u00a04-pole and 6-pole structures were analyzed\u00a0consisting of arbitrary cascades. Unapodized and\u00a0withdrawal weighted SAW transducers have been\u00a0employed.<\/p>\n<h2 style=\"text-align: justify;\">PRELIMINARY EXPERIMENTAL RESULTS<\/h2>\n<p style=\"text-align: justify;\">The 4-pole resonator filters having the structure shown in Fig.1 have been manufactured for comparative analysis of various LiNbO3 cuts. The number of electrodes in the middle IDT was 33 and every lateral IDT had 25 electrodes. Metallization thickness was 0.3 mm (h\/l ~0.03), and the aperture width 430 mm. The frequency response of the filter with 64\u00b0 -YX LiNbO3 substrate is shown in Fig.2 and the main parameters for filters based on three different cuts of LiNbO3 are presented in Table 1. It should be mentioned that these parameters were obtained using LC matching circuits (except for the 64\u00b0 -YX filter).<\/p>\n<h3 style=\"text-align: justify;\">Table 1 Parameters of filters based on different LiNbO3 cuts<\/h3>\n<p style=\"text-align: justify;\"><a href=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic90.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-5504\" src=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic90.jpg\" alt=\"Table 1 Parameters of filters based on different LiNbO3 cuts\" width=\"370\" height=\"170\" srcset=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic90.jpg 370w, https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic90-190x87.jpg 190w, https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic90-300x137.jpg 300w, https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic90-140x64.jpg 140w\" sizes=\"auto, (max-width: 370px) 100vw, 370px\" \/><\/a><\/p>\n<p style=\"text-align: justify;\">The filters manufactured on the substrates with\u00a0higher k2 have wider passbands, but greater insertion\u00a0loss compared to 64\u00b0 -YX cut. It is caused not only\u00a0by higher propagation loss but also by the excess of<br \/>\nelectrode number in test structures for these cuts. In\u00a0order to determine the major substrate parameters as\u00a0functions of metal film thickness, several filter\u00a0samples were manufactured. with various thicknesses,\u00a0h\/l from 0.01 to 0.06.<\/p>\n<p style=\"text-align: justify;\">The experimental examination of test structures\u00a0and the comparison of their parameters with\u00a0simulated ones enabled to calculate the values of\u00a0electro-mechanical coupling and frequency behavior\u00a0of reflection and absorption coefficients versus\u00a0metallization thickness. In particular, for film\u00a0thickness h\/l=0.05-0.06 the observed effective\u00a0coupling coefficient was 20-22%, that is greater by\u00a010-15% compared to its value for h\/l=0 [3]. Similar\u00a0results were earlier obtained for 36\u00b0 -YX cut of\u00a0LiTaO3 [5].<\/p>\n<p style=\"text-align: justify;\">The accurate values of electro-physical constants\u00a0obtained from preliminary experimental results were\u00a0further used to improve the tuning of model and to\u00a0provide the better meeting of simulated and\u00a0experimental results while filter design.<\/p>\n<p style=\"text-align: justify;\">To evaluate the temperature behavior, filter\u00a0measurements were carried out within the interval\u00a0from -25 to +75 \u00b0C. The average temperature\u00a0coefficients are 68 ppm\/\u00b0C for both examined cuts of \u00a0LiNbO3. It should be mentioned that the temperature\u00a0coefficients for a LCRF are better than that of the\u00a0pure substrate from [3].<\/p>\n<h2 style=\"text-align: justify;\">IV. FILTER DESIGN<\/h2>\n<p style=\"text-align: justify;\">The experimental response of 4-pole filter with\u00a0the structure shown in Fig.1(a) is presented in Fig.3.The filter was built on 41\u00b0-YX LiNbO3 substrate.\u00a0The number of electrodes in the middle IDT is 21\u00a0and each lateral IDT has 19 electrodes. All<\/p>\n<div id=\"attachment_5502\" style=\"width: 368px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic91.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5502\" class=\"size-full wp-image-5502\" src=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic91.jpg\" alt=\"Fig.3 The experimental frequency response S21 for the 405 MHz resonator filter on the\u00a0substrate of 41\u00b0 -YX LiNbO3,. Insertion loss is 2.7dB, fractional bandwidth is 7.1% .\" width=\"358\" height=\"276\" \/><\/a><p id=\"caption-attachment-5502\" class=\"wp-caption-text\">Fig.3 The experimental frequency response S21 for the 405 MHz resonator filter on the\u00a0substrate of 41\u00b0 -YX LiNbO3,. Insertion loss is 2.7dB, fractional bandwidth is 7.1% .<\/p><\/div>\n<p style=\"text-align: justify;\">transducers are unapodized. IDT aperture width is\u00a060l. The ratio of IDT and grating periods is 0.98.\u00a0Al film thickness is 0.6 mm (h\/l=0.06). Serial\u00a0inductances at the input and the output are used for\u00a0filter matching in 50-Ohm track. The measured\u00a0filter passband is 28.8 MHz (or 7.1%) and the\u00a0insertion loss is 2.8 dB. The signal suppression in\u00a0stopband is more than 45 dB. Similar characteristics\u00a0were obtained for 49\u00b0 -YX cut. For metal film\u00a0thickness 0.52 mm the measured passband was 6.4%\u00a0and the insertion loss was 2.7 dB.<\/p>\n<p style=\"text-align: justify;\">The typical feature of filters made on the\u00a0investigated cuts of LiNbO3 is the presence of\u00a0spurious resonances in the lower frequency stopband\u00a0(see fig. 3). For 41\u00b0 -YX LiNbO3 cut these spurious\u00a0modes are somewhat higher (by 5-8 dB).<\/p>\n<div id=\"attachment_5500\" style=\"width: 368px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic92.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5500\" class=\"size-full wp-image-5500\" src=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic92.jpg\" alt=\"Fig.4 The simulated (1) and experimental (2)\u00a0frequency responses\u00bdS21\u00bd of the 415 MHz\u00a0resonator filter with shifted periods in cascades. Substrate is 49\u00b0 -YX LiNbO3, Insertion loss is 2.7,\u00a0fractional bandwidth is 6.2%\" width=\"358\" height=\"276\" \/><\/a><p id=\"caption-attachment-5500\" class=\"wp-caption-text\">Fig.4 The simulated (1) and experimental (2)\u00a0frequency responses\u00bdS21\u00bd of the 415 MHz\u00a0resonator filter with shifted periods in cascades. Substrate is 49\u00b0 -YX LiNbO3, Insertion loss is 2.7,\u00a0fractional bandwidth is 6.2%<\/p><\/div>\n<p style=\"text-align: justify;\">The filter structures with different electrode\u00a0periods in sections were investigated in order to\u00a0reduce the narrowband resonance peaks. The shift in\u00a0periods of two filter cascades was 0.2%. Fig.4 shows\u00a0the experimental response S21 of the 415 MHz filter\u00a0built on 49\u00b0-YX LiNbO3. It was found that the\u00a0amplitudes of resonance peaks in the stopband are not\u00a0higher than that of actual filter ripples. For\u00a0comparison the simulated filter characteristic is also\u00a0shown in the same figure. The agreement between the\u00a0simulated and the experimental responses is very\u00a0good. Somewhat higher experimental suppression\u00a0in the high-frequency stopband can be explained by\u00a0the frequency dependence of an absorption\u00a0coefficient which increases anomalously at the\u00a0frequencies higher than that of an acoustic\u00a0synchronism [5].<\/p>\n<p style=\"text-align: justify;\">LCRFs with apodized IDTs were designed in order\u00a0to improve the filter selectivity. As an example of such structure, the 426 MHz filter was built on\u00a049\u00b0 -YX LiNbO3. The measured and the simulated\u00a0frequency responses are presented in Fig.5. The\u00a0center IDT in each cascade was made withdrawal\u00a0weighted, 25l length. The lateral IDTs had 17\u00a0unapodized electrodes each. The obtained passband\u00a0was 25 MHz (6.0%) while the electrode thickness\u00a0was 0.5 mm - this value is slightly less than in the\u00a0case of unapodized IDTs. The insertion loss was 2.1\u00a0dB and the sidelobe suppression about 60 dB. The\u00a0electrical matching for 75-Ohm track was performed\u00a0using inductances connected in series at the input and\u00a0at the output filter ports.<\/p>\n<div id=\"attachment_5498\" style=\"width: 368px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic93.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-5498\" class=\"size-full wp-image-5498\" src=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic93.jpg\" alt=\"Fig.5 The experimental (1) and the simulated (2)\u00a0frequency responses \u00bdS21\u00bd for the 460 MHz\u00a0resonator filter with withdrawal weighted IDTs.\u00a0Substrate is 49\u00b0 -YX LiNbO3, Insertion loss is 2.1\u00a0dB, fractional bandwidth is 6.0%.\" width=\"358\" height=\"276\" \/><\/a><p id=\"caption-attachment-5498\" class=\"wp-caption-text\">Fig.5 The experimental (1) and the simulated (2)\u00a0frequency responses \u00bdS21\u00bd for the 460 MHz\u00a0resonator filter with withdrawal weighted IDTs.\u00a0Substrate is 49\u00b0 -YX LiNbO3, Insertion loss is 2.1\u00a0dB, fractional bandwidth is 6.0%.<\/p><\/div>\n<h2>CONCLUSIONS<\/h2>\n<p style=\"text-align: justify;\">The cuts of LiNbO3 which are known to have high\u00a0electromechanical coupling coefficient for leaky\u00a0waves - 41\u00b0-YX and 49\u00b0-YX, are shown to be\u00a0promising as substrates for low-loss filters with\u00a0fractional bandwidth up to 10%. Thick Al electrodes\u00a0(h\/l=0.05) enabled to increase the effective coupling coefficient up to 20-22%. The spurious SAW modes generated in analyzed cuts can be successfully suppressed by means of frequency shift between two cascades of filter. The equivalent circuit model has been modified to account for mechanical reflections and frequency dependent character of attenuation coefficient for leaky waves in thick electrode structure. Charge distribution on the electrodes was taken into account to improve the model accuracy. As a result, very good agreement between simulated and experimental frequency responses has been achieved. Low loss (2-3 dB) longitudinally coupled resonator filters with fractional bandwidth 7% and sidelobe suppression 50-60 dB have been designed and manufactured.<\/p>\n<h2 style=\"text-align: justify;\">ACKNOWLEDGMENT<\/h2>\n<p style=\"text-align: justify;\">This work was supported in part by TELEFILTER tft GmbH. The authors would like to thank Dr.N.F.Naumenko for helpful advices.<\/p>\n<h2 style=\"text-align: justify;\">REFERENCES<\/h2>\n<ol>\n<li style=\"text-align: justify;\">T. Morita and et. al. \"Low loss double mode SAW\u00a0filters\", 1992 Ultrasonics Symposium Proc., pp. 95\u00a0-104.<\/li>\n<li style=\"text-align: justify;\">Y.Kuroda, S.Ichikava, S.Mitobe, M.Koshono \"Wide\u00a0bandwidth SAW resonator filter using 36 Y-X\u00a0LiTaO3\", IEICE Trans. Fundamental, vol.E78-\u00a0A,No.5, 1995.<\/li>\n<li style=\"text-align: justify;\">T.Sato, H.Abe \"Propagation properties of\u00a0longitudinal leaky surface waves on lithium\u00a0tetraborate\", 1994 Ultrasonics Symposium Proc.,\u00a0p.292.<\/li>\n<li style=\"text-align: justify;\">M.Hikita, A.Isobe, N.Sumioka, N.Matsuura and\u00a0K.Okazaki \"New rigorous treatment of leaky SAWs\u00a0and its application to high-performance filters used\u00a0in mobile pocket phones\", 1994 Ultrasonics Symposium Proc., pp.207-212.<\/li>\n<li style=\"text-align: justify;\">V.P.Plessky \"A two parameter coupling-of-modes\u00a0model for shear horizontal type SAW propagation in\u00a0periodic gratings\" 1993 Ultrasonics Symposium\u00a0Proc., pp.195-200<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>The possibility of utilizing cuts of LiNbO3\u00a0with high piezoelectric coupling for leaky waves - 41\u00b0-YX and 49\u00b0-YX - in wideband SAW filters, has been\u00a0demonstrated. The equivalent circuit model was\u00a0modified for longitudinally coupled resonator filters and\u00a0some second-order effects have been taken into account\u00a0to improve the accuracy of filter simulation. Thick Al\u00a0electrodes are used to increase the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[8],"tags":[],"class_list":["post-5465","post","type-post","status-publish","format-standard","hentry","category-articles-en"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Wideband low loss SAW filters for telecommunication and mobile radio applications - Butis<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/butis-m.ru\/en\/articles-en\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Wideband low loss SAW filters for telecommunication and mobile radio applications - Butis\" \/>\n<meta property=\"og:description\" content=\"The possibility of utilizing cuts of LiNbO3\u00a0with high piezoelectric coupling for leaky waves - 41\u00b0-YX and 49\u00b0-YX - in wideband SAW filters, has been\u00a0demonstrated. The equivalent circuit model was\u00a0modified for longitudinally coupled resonator filters and\u00a0some second-order effects have been taken into account\u00a0to improve the accuracy of filter simulation. Thick Al\u00a0electrodes are used to increase the [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/butis-m.ru\/en\/articles-en\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\/\" \/>\n<meta property=\"og:site_name\" content=\"Butis\" \/>\n<meta property=\"article:published_time\" content=\"2014-07-10T15:42:36+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2014-08-17T07:22:01+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/butis-m.ru\/wp-content\/uploads\/2014\/07\/Pic88.jpg\" \/>\n<meta name=\"author\" content=\"abutis\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"abutis\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"9 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/butis-m.ru\\\/en\\\/articles-en\\\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/butis-m.ru\\\/en\\\/articles-en\\\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\\\/\"},\"author\":{\"name\":\"abutis\",\"@id\":\"https:\\\/\\\/butis-m.ru\\\/ru\\\/#\\\/schema\\\/person\\\/f6d022145d542f3bdaad5d9863a9ce2e\"},\"headline\":\"Wideband low loss SAW filters for telecommunication and mobile radio applications\",\"datePublished\":\"2014-07-10T15:42:36+00:00\",\"dateModified\":\"2014-08-17T07:22:01+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/butis-m.ru\\\/en\\\/articles-en\\\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\\\/\"},\"wordCount\":1807,\"image\":{\"@id\":\"https:\\\/\\\/butis-m.ru\\\/en\\\/articles-en\\\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/butis-m.ru\\\/wp-content\\\/uploads\\\/2014\\\/07\\\/Pic88.jpg\",\"articleSection\":[\"Articles\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/butis-m.ru\\\/en\\\/articles-en\\\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\\\/\",\"url\":\"https:\\\/\\\/butis-m.ru\\\/en\\\/articles-en\\\/wideband-low-loss-saw-filters-for-telecommunication-and-mobile-radio-applications\\\/\",\"name\":\"Wideband low loss SAW filters for telecommunication and mobile radio applications - 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