Design and Characterization of a 37 GHz Millimeter-Wave Transceiver for Dielectric-Based Sensing in Aqueous Solutions

Abstract

Diabetes is a chronic disease requiring frequent monitoring of blood glucose levels, while conventional invasive techniques remain painful and inconvenient. In this work, we present a compact millimeter-wave (mm-wave) transceiver operating at 37 GHz for non-invasive glucose sensing based on variations in the dielectric properties of biological media. The proposed system operates in transmission mode using a pair of microstrip patch antennas, where changes in glucose concentration alter the complex permittivity of the medium, which in turn affects the transmission coefficient (S21) of the propagating signal. These variations in S21 lead to measurable changes in the received power, which are converted into a DC voltage using a power detector, enabling quantitative estimation of glucose levels. The transceiver integrates a voltage-controlled oscillator, frequency tripler, low-noise amplifier, and power detector to realize a compact and low-cost sensing platform. The relationship between glucose concentration, permittivity, and transmission loss is analyzed through theoretical modeling and electromagnetic simulations. Experimental validation using aqueous and blood-mimicking solutions demonstrates a strong linear correlation between glucose concentration and detector output voltage. The system achieves a detection resolution of approximately 200.4 mg/dL, currently limited by measurement instrumentation. These results confirm the feasibility of mm-wave transmission-based sensing for non-invasive glucose monitoring, with strong potential for future development of portable and continuous glucose monitoring devices.

Keywords

• Millimeter-wave sensing
• non-invasive glucose monitoring
• RF biosensors
• transmission coefficient (S21)
• dielectric permittivity
• microwave sensing
• biomedical sensors
• patch antenna
• glucose detection
• mm-wave transceiver.

Sulu Çözeltilerde Dielektrik Tabanlı Algılama için 37 GHz Milimetre-Dalga Alıcı-Vericisinin Tasarımı ve Karakterizasyonu

Abstract

Diyabet, kan glukoz seviyelerinin sık sık izlenmesini gerektiren kronik bir hastalıktır; ancak geleneksel girişimsel teknikler ağrılı ve zahmetli olmaya devam etmektedir. Bu çalışmada, biyolojik ortamların dielektrik özelliklerindeki değişimlere dayanarak girişimsel olmayan glukoz algılaması için 37 GHz frekansında çalışan kompakt bir milimetre-dalga (mm-wave) alıcı-vericisi sunuyoruz. Önerilen sistem, bir çift mikroşerit yama anten kullanarak iletim modunda çalışmaktadır; burada glukoz konsantrasyonundaki değişimler ortamın karmaşık geçirgenliğini değiştirmekte, bu da yayılan sinyalin iletim katsayısını (S21) etkilemektedir. S21 katsayısındaki bu varyasyonlar, alınan güçte ölçülebilir değişimlere yol açmakta ve bir güç detektörü vasıtasıyla DC voltajına dönüştürülerek glukoz seviyelerinin nicel olarak tahmin edilmesini sağlamaktadır. Alıcı-verici; kompakt ve düşük maliyetli bir algılama platformu gerçekleştirmek amacıyla bir voltaj kontrollü osilatör, frekans üçleyici, düşük gürültülü amplifikatör ve güç detektörünü entegre etmektedir. Glukoz konsantrasyonu, geçirgenlik ve iletim kaybı arasındaki ilişki, teorik modelleme ve elektromanyetik simülasyonlar aracılığıyla analiz edilmiştir. Sulu ve kan taklit eden çözeltiler kullanılarak yapılan deneysel doğrulama, glukoz konsantrasyonu ile detektör çıkış voltajı arasında güçlü bir doğrusal korelasyon olduğunu göstermektedir. Sistem, şu anda ölçüm enstrümantasyonu ile sınırlı olmak üzere yaklaşık 200.4 mg/dL'lik bir tespit çözünürlüğü elde etmektedir. Bu sonuçlar, girişimsel olmayan glukoz takibi için mm-dalga iletim tabanlı algılamanın uygulanabilirliğini doğrulamakta ve taşınabilir ile sürekli glukoz izleme cihazlarının gelecekteki gelişimi için güçlü bir potansiyel sunmaktadır.

Keywords

• Milimetre-dalga algılama
• girişimsel olmayan glukoz takibi
• RF biyosensörleri
• iletim katsayısı (S21)
• dielektrik geçirgenlik
• mikrodalga algılama
• biyomedikal sensörler
• yama anten
• glukoz tespiti
• mm-dalga alıcı-vericisi

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