Automotive Active Antenna Design for AM/FM Radio System

Öz

This article examines the historical evolution of automobile antennas and highlights the importance of modern smart antenna designs. The long rod antennas, approximately 1.5 meters in length, used in the 1970s were replaced by active AM/FM antennas integrated into vehicle windows starting in 1984. Today, spiral antenna designs measuring 5-15 cm in length are widely used to enhance antenna performance, provide aerodynamic advantages, and comply with electromagnetic compatibility regulations. The article also explores innovations such as antenna integration for digital video broadcasting (DVB) and V2X communication systems, high-impedance amplifiers (with gains typically ranging from 15-25 dB), and triband antennas. The optimization of parameters such as impedance matching, gain, stability, and noise (typically 1-2 dB) during the active antenna design process is emphasized as crucial for improving antenna performance and electromagnetic immunity. As part of the study, a 40 cm rod antenna equipped with an amplifier operating in the AM and FM bands and with a noise level of 1.2 dB was designed. The antenna was tested on a vehicle, and the signal strength was measured using a Rigol Spectrum Analyzer. It was observed that the signal noise level was 1 dB lower compared to the original device. The helical structure of the designed antenna set the resonance frequency at 180 MHz. Additionally, the longer strip length compared to the antenna’s physical length reduced the capacitive input impedance, contributing to enhanced antenna performance through this key technical innovation.

Anahtar Kelimeler

• Automotive antennas
• rod atennas
• AM/FM radio systems

AM/FM Radyo Sistemleri için Otomotiv Aktif Çubuk Anten Tasarımı

Öz

Bu makale, otomobil antenlerinin tarihsel gelişimini ve günümüz akıllı anten tasarımlarının önemini incelemektedir. 1970'lerde kullanılan yaklaşık 1.5 metre uzunluğundaki çubuk antenlerin yerini, 1984'ten itibaren araç camlarına entegre edilen aktif AM/FM antenler almıştır. Günümüzde ise 5-15 cm boyutlarındaki sarmal anten tasarımları, anten performansını artırmak, aerodinamik avantaj sağlamak ve elektromanyetik uyumluluk düzenlemelerine uyum göstermek için yaygın olarak kullanılmaktadır. Makale, sayısal video yayını (SVY) ve V2X iletişim sistemleri gibi modern uygulamalara yönelik anten entegrasyonu, yüksek empedanslı amplifikatörler (15-25 dB kazanç) ve triband antenler gibi yeniliklere de değinmektedir. Aktif anten tasarım sürecinde empedans uyumu, kazanç, kararlılık ve gürültü gibi parametrelerin optimize edilmesinin, anten performansını ve elektromanyetik bağışıklığı artırmak için kritik olduğu vurgulanmıştır. Çalışma kapsamında, AM ve FM bantlarında çalışan, 1.2 dB gürültü seviyesine sahip bir yükseltici ile donatılmış 40 cm boyunda bir çubuk anten tasarlanmıştır. Anten, araç üzerinde test edilmiş ve alınan sinyalin güç değeri Rigol Spectrum Analizör ile ölçülmüştür. Orijinal cihazla kıyaslandığında sinyalin gürültü seviyesinin 1 dB daha düşük olduğu gözlenmiştir. Tasarımda kullanılan helisel yapı, rezonans frekansını 180 MHz’e ayarlamış ve şerit boyunun anten boyundan uzun olması sayesinde kapasitif giriş empedansını düşürmüştür. Bu, antenin performansını artıran önemli bir teknik yenilik olarak öne çıkmıştır.

Anahtar Kelimeler

• Otomotiv Antenleri
• Çubuk antenleri
• AM/FM radyo sistemleri

Kaynakça

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